Ultimate Baked Tomato and Squash Casserole: A Healthy & Flavorful Summer Delight
If you’re searching for a dish that brings together the fresh flavors of summer, vibrant colors, and wholesome goodness, look no further than this incredible **Tomato and Squash Casserole**. This delightful bake features tender zucchini, bright yellow squash, and juicy Roma tomatoes, all elevated by the aromatic touch of fresh oregano and the rich, nutty notes of Parmesan cheese. It’s a truly satisfying, nutrient-packed meal or side dish that adds a burst of sunshine to any table.
Perfect for harnessing the abundant harvest of late summer and early fall, this layered vegetable casserole is not just a feast for the eyes but also a treat for the taste buds. It’s a simple yet elegant way to enjoy seasonal produce at its best, transforming humble vegetables into a comforting and flavorful experience. Whether served as a hearty vegetarian main course or a vibrant side, this casserole is sure to become a cherished recipe in your culinary repertoire.
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Just like our popular Zucchini Quiche, this casserole is a fantastic solution for using up an abundance of garden zucchini. If you find yourself with a surplus of these versatile green gourds, consider baking a batch of Zucchini Bread as another delicious option!
This recipe celebrates simplicity and the natural goodness of fresh vegetables. It’s designed to be straightforward, making it accessible for home cooks of all skill levels. With minimal effort, you can create a stunning and nutritious dish that tastes like it came from a gourmet kitchen. Let’s dive into what makes this casserole so special and how you can bring it to your own table.
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Why You’ll Love This Tomato & Squash Casserole
- Bursting with Fresh Flavors: The combination of ripe tomatoes, tender squash, aromatic oregano, and savory Parmesan creates a symphony of flavors that is truly unforgettable. Each bite offers a taste of the garden.
- Nutrient-Rich and Wholesome: Packed with vitamins, minerals, and fiber from the fresh vegetables, this casserole is a guilt-free indulgence that supports a healthy lifestyle. It’s a delicious way to boost your daily vegetable intake.
- Visually Stunning: The vibrant reds, yellows, and greens of the layered vegetables make this dish incredibly appealing. It’s a showstopper that will impress your guests and brighten up your dinner table.
- Easy to Prepare: Despite its impressive appearance, this casserole requires simple slicing and layering, making it an ideal recipe for busy weeknights or relaxed weekend meals. No complicated techniques or lengthy cooking times are involved.
- Incredibly Versatile: Serve it as a light vegetarian main course, a hearty side dish to grilled meats or fish, or even for brunch. Its adaptability means it fits into various meal plans and occasions.
- Perfect for Seasonal Eating: This recipe shines when made with fresh, in-season produce. It’s a fantastic way to utilize your garden bounty or pick up the best ingredients from your local farmer’s market.
- Naturally Gluten-Free & Vegetarian: Catering to various dietary needs, this casserole is a fantastic option for those seeking wholesome, plant-based meals that are free from gluten.
Video Guide
Watch our step-by-step video to see just how easy it is to assemble this beautiful and delicious tomato and squash casserole. Perfect for visual learners, this video will guide you through each stage of the preparation, ensuring your dish turns out perfectly every time.
Essential Ingredients for Your Tomato & Squash Casserole
Creating a truly remarkable dish begins with high-quality ingredients. For this casserole, freshness is key to unlocking its full flavor potential. Here’s a breakdown of what you’ll need, along with tips for selecting the best produce:
- Yellow Squash: Look for firm, bright yellow squash without blemishes. Its mild, slightly sweet flavor and tender texture add a lovely component to the casserole.
- Zucchini: Choose small to medium-sized zucchini that are firm and smooth. They offer a delicate flavor and absorb the other delicious seasonings wonderfully.
- Green Onion: Provides a subtle, fresh onion flavor that complements the other vegetables without overpowering them. Both the white and green parts are used.
- Fresh Oregano: The star herb in this dish, fresh oregano delivers a pungent, peppery, and slightly sweet aroma. Using fresh herbs makes a significant difference in the final taste. If fresh isn’t available, see our substitution note in the recipe card.
- Roma Tomatoes: Also known as plum tomatoes, Romas are ideal for slicing as they have less water content and a firm flesh, preventing the casserole from becoming too watery. Select firm, deeply colored tomatoes.
- Olive Oil: A good quality extra virgin olive oil adds richness and helps the vegetables caramelize slightly as they bake, enhancing their natural sweetness.
- Parmesan Cheese: Freshly shredded Parmesan cheese provides a salty, umami-rich, and nutty flavor that perfectly binds all the ingredients together. Its golden crust on top is irresistible.
- Garlic Cloves: Essential for any savory dish, fresh garlic adds a pungent and aromatic depth of flavor. Minced garlic integrates beautifully into the herb and cheese mixture.
- Freshly Ground Black Pepper: For a fresh, piquant kick that enhances the overall seasoning.
- Salt: Balances the flavors and helps draw out moisture from the vegetables, concentrating their taste.
- Non-stick Spray: To ensure your delicious casserole doesn’t stick to the baking dish, making serving and cleanup a breeze.
For precise quantities, please refer to the detailed recipe card below.
Step-by-Step: Crafting Your Perfect Tomato & Squash Casserole
This casserole is incredibly easy to assemble, featuring simple layering that builds both flavor and visual appeal. Follow these steps to create a delicious and satisfying dish:
1. Prepare Your Aromatics: Begin by thoroughly washing all your vegetables. Next, mince the garlic cloves and finely chop the green onions and fresh oregano leaves (1). The finer you chop, the more evenly their flavors will distribute. Transfer these aromatic ingredients to a small bowl and mix them with the shredded Parmesan cheese (2). This mixture will be key to the casserole’s incredible flavor.
2. Slice the Squash and Season: Slice the zucchini and yellow squash into even rounds, approximately ¼-inch thick. Aim for uniform thickness to ensure they cook evenly. Place the sliced squash in a bowl and toss them generously with salt and freshly ground black pepper (3). This seasoning will help draw out some moisture and infuse flavor into the squash. Set aside.
3. Slice the Tomatoes: Slice the Roma tomatoes into rounds of similar thickness to the squash (4). Roma tomatoes are ideal here due to their lower water content, which helps prevent the casserole from becoming overly liquidy.
4. Layering the Casserole: Preheat your oven to 400°F (200°C). Prepare a shallow baking dish (a 9×13 inch dish or similar size works well) by coating it generously with non-stick cooking spray. Arrange half of the seasoned zucchini and yellow squash slices in an even layer at the bottom of the dish (5). Try to overlap them slightly for a full coverage.
5. Add Tomatoes and Cheese: Carefully layer half of the sliced Roma tomatoes over the squash (6). Then, sprinkle this layer with half of the Parmesan cheese, garlic, green onion, and oregano mixture (7). This ensures flavor in every bite!
6. Repeat and Finish: Repeat the layering process with the remaining squash, tomatoes, and cheese mixture (8). Once all layers are in place, drizzle the entire casserole with 1 tablespoon of olive oil. If desired, you can add an extra sprinkle of salt and pepper on top for a final touch of seasoning.
7. Bake to Perfection: Place the casserole in the preheated oven and bake for 30 minutes, or until the vegetables are tender and the cheese is melted and bubbly with a golden crust. The exact baking time may vary slightly depending on your oven and the thickness of your vegetable slices.
8. Rest Before Serving: Once baked, remove the casserole from the oven and allow it to sit for 10 minutes before serving. This resting period is crucial as it allows the flavors to meld and the casserole to set, making it easier to serve and preventing it from falling apart.
Substitutions & Creative Variations
This Tomato and Squash Casserole is wonderfully adaptable, making it easy to fit various dietary needs or simply to experiment with different flavors. Here are some ideas:
Dietary Adjustments:
- Vegetarian & Gluten-Free: As written, this recipe is already both vegetarian and gluten-free, making it a fantastic option for many.
- Vegan & Dairy-Free: To make this dish suitable for vegans or those avoiding dairy, simply omit the Parmesan cheese or substitute it with your favorite plant-based shredded cheese alternative. Nutritional yeast can also add a cheesy, umami flavor.
Adding Protein:
To transform this delightful side dish into a more substantial main course, consider adding a source of protein:
- Chicken: Layer thin slices of pre-cooked, seasoned chicken breast or shredded rotisserie chicken between the vegetable layers.
- Tofu or Tempeh: Cubed and pan-fried tofu or tempeh can be added for a plant-based protein boost. Marinate it first for extra flavor.
- Sausage: Cooked and crumbled Italian sausage (pork or plant-based) can add a rich, savory depth.
- Beans or Lentils: A layer of cooked cannellini beans or green lentils would add fiber and plant-based protein.
Flavor Enhancements & Other Vegetables:
- Other Vegetables: Feel free to incorporate other seasonal vegetables such as thinly sliced eggplant, bell peppers, thinly sliced onions, or even a layer of fresh spinach leaves.
- Different Herbs: While oregano is classic, fresh basil, thyme, or a blend of Italian herbs would also be delicious.
- Cheese Alternatives: Instead of or in addition to Parmesan, try shredded mozzarella, a sprinkle of sharp cheddar, or crumbled feta for a tangy twist.
- Spice it Up: A pinch of red pepper flakes can add a subtle kick if you enjoy a bit of heat.
- Crunchy Topping: For an extra layer of texture, mix some panko breadcrumbs with a little melted butter and sprinkle over the top during the last 10 minutes of baking.
Serving Suggestions for Your Casserole
This versatile Tomato and Squash Casserole pairs beautifully with a variety of dishes, making it an excellent addition to almost any meal. Here are some ideas to inspire you:
- As a Side Dish: It’s a perfect accompaniment to grilled chicken, roasted turkey, pan-seared fish (like salmon or cod), or a juicy steak. The light and fresh flavors of the casserole complement richer main courses beautifully.
- As a Light Main Course: For a satisfying vegetarian meal, serve a larger portion of the casserole with a crisp green salad tossed in a simple vinaigrette and a side of crusty artisan bread for dipping into the delicious juices.
- Brunch Option: Unexpected but delightful! Serve alongside scrambled eggs, a frittata, or even a simple quiche for a flavorful and colorful brunch spread.
- Potluck or Holiday Dish: Its impressive appearance and crowd-pleasing flavors make it an ideal dish to bring to a potluck, family gathering, or holiday feast. It holds up well and is delicious served warm or at room temperature.
- With Grains: Pair it with a side of quinoa, brown rice, or couscous for a more complete and filling meal, absorbing the delicious vegetable juices.
Storage and Freezing Tips
Proper storage ensures you can enjoy the leftovers of this delicious casserole for days to come. While freezing is possible, it’s worth noting how it might affect the texture:
Storage:
Store any leftover Tomato and Squash Casserole in an airtight container in the refrigerator for up to 4 days. Make sure it cools completely before refrigerating to prevent condensation.
Reheating:
To reheat, you can warm individual servings in the microwave until heated through. For larger portions, place the casserole back in a preheated oven at 350°F (175°C) for 15-20 minutes, or until bubbling and hot, covering with foil if it starts to brown too much.
Freezing:
While technically freezable, squash can become slightly watery and lose some of its firm texture after thawing. If you choose to freeze, bake the casserole completely, allow it to cool, then wrap it tightly in plastic wrap and then foil. It can be frozen for up to 2-3 months. Thaw overnight in the refrigerator before reheating in the oven.
Tips for a Perfect Casserole Every Time
Achieving a perfectly tender and flavorful casserole is easy with a few simple tips:
- Uniform Slicing: Slice your zucchini, yellow squash, and tomatoes to a consistent ¼-inch thickness. This ensures even cooking, so all vegetables become tender at the same rate.
- Don’t Skip the Salt & Pepper on Squash: Tossing the squash with salt and pepper before layering not only seasons it but also helps draw out excess moisture. This is especially important for zucchini, which can release a lot of water during baking, preventing a watery casserole. You can even let it sit for 15-20 minutes after salting and then pat dry before layering for extra moisture control.
- Fresh Herbs Make a Difference: While dried oregano can be used in a pinch (see recipe notes for conversion), fresh oregano truly elevates the aroma and flavor of this dish.
- Grate Your Own Parmesan: Freshly grated Parmesan cheese melts better and has a superior flavor compared to pre-shredded varieties, which often contain anti-caking agents.
- Avoid Overcrowding: Use a baking dish that allows for a good, even distribution of vegetables. If your dish is too small, the vegetables will steam rather than bake, resulting in a less desirable texture.
- The Power of Fresh Herbs: This layered squash and tomato bake is the perfect recipe to showcase fresh herbs, and it’s also a great excuse to start your own herb garden!
I like to keep fresh herbs growing all year, either in a planter outside or on a south-facing windowsill inside during the cold months. For almost the same price as a single packet of fresh-cut herbs, you can buy a live herb plant that will produce all year long, providing endless fresh flavor for your cooking!
Frequently Asked Questions (FAQ)
-
Can I use different types of squash?
Yes, absolutely! While zucchini and yellow squash are traditional, you can experiment with other summer squash varieties like pattypan squash. Ensure they are sliced thinly and consistently for even cooking. -
What if I don’t have fresh oregano?
If fresh oregano isn’t available, you can use dried oregano. As a general rule, use about ⅓ the amount of dried herbs compared to fresh. For this recipe, 1 teaspoon of dried oregano would be a good substitute for 1 tablespoon of fresh. -
Can I prepare this casserole ahead of time?
You can prepare and layer the casserole up to a day in advance. Cover it tightly with plastic wrap and refrigerate. Let it come closer to room temperature for about 30 minutes before baking, and you might need to add an extra 5-10 minutes to the baking time. -
How do I prevent the casserole from being watery?
Several steps help with this:- Use Roma tomatoes, which have less water.
- Toss the squash with salt and pepper; this helps draw out some moisture before baking. You can even let the salted squash sit for 15-20 minutes and then gently pat it dry with paper towels before layering.
- Don’t overcrowd the baking dish; allow some space for steam to escape.
- Ensure your oven is preheated to the correct temperature.
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What kind of baking dish is best?
A shallow 9×13 inch (23×33 cm) casserole dish or a similar sized gratin dish works best. The shallow depth allows the vegetables to roast slightly and the cheese to brown nicely.
Recipe Card
Tomato and Squash Casserole
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Ingredients
- 1 zucchini
- 2 yellow squash
- 4 Roma tomatoes
- 2 cloves garlic, minced
- 2 green onions, chopped
- 1 tablespoon fresh oregano leaves, chopped
- 1 cup shredded Parmesan cheese
- ½ teaspoon salt
- ½ teaspoon freshly ground black pepper
- 1 tablespoon olive oil
- Non-stick cooking spray
Instructions
- Wash all vegetables thoroughly.
- Mince 2 cloves garlic and chop 2 green onions and 1 tablespoon fresh oregano leaves. Combine in a bowl with 1 cup shredded Parmesan cheese and set aside.
- Slice 1 zucchini and 2 yellow squash into ¼-inch rounds and toss with ½ teaspoon salt and ½ teaspoon freshly ground black pepper.
- Preheat oven to 400°F (200°C). Prepare a shallow baking dish with non-stick cooking spray.
- Layer ½ of the seasoned zucchini and squash in the prepared baking dish.
- Slice 4 Roma tomatoes into ¼-inch rounds and layer half of the tomato slices over the squash.
- Sprinkle with ½ of the Parmesan cheese mixture.
- Repeat layers with the remaining squash, tomatoes, and cheese mixture.
- Drizzle with 1 tablespoon olive oil and sprinkle with more salt and pepper if desired.
- Bake at 400°F (200°C) for 30 minutes, or until vegetables are tender and cheese is bubbly and golden. Allow to sit for 10 minutes before serving.
Notes
- If you do not have access to fresh oregano, you can use 1 teaspoon dried oregano.
- Vegans and those avoiding dairy can omit the Parmesan cheese or use a dairy-free alternative.
Adapted from a recipe in Costco Connection magazine.
Nutrition per serving
Carbohydrates: 8 g
Protein: 8 g
Fat: 7 g
Sodium: 662 mg
Fiber: 3 g
Sugar: 4 g
Net Carbohydrates: 5 g
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This delicious tomato and squash dish, brimming with fresh flavors and an inviting aroma, is adapted from a recipe originally featured in the Costco Connection magazine. We’ve enhanced it to be even more approachable and flavorful for your home kitchen.
Embrace the Harvest with This Flavorful Casserole
This Tomato and Squash Casserole is more than just a recipe; it’s a celebration of fresh, seasonal ingredients and the joy of simple, wholesome cooking. With its vibrant colors, delightful textures, and rich, aromatic flavors, it truly embodies the essence of late summer and early fall. Whether you’re a seasoned chef or a novice in the kitchen, this dish offers an easy and rewarding cooking experience, delivering delicious results every time.
We encourage you to try this recipe and make it your own. Experiment with the variations, adjust the seasonings to your taste, and most importantly, enjoy the process of creating something truly special. It’s a fantastic way to nourish your body, delight your palate, and share a comforting meal with loved ones. We hope this casserole brings a little extra sunshine and flavor to your table, just as it has to ours!