Watch Our Tomato and Squash Casserole Recipe Video

Get a visual guide to preparing this beautiful tomato and squash casserole! This video walks you through each step, ensuring you achieve perfect layers and a wonderfully baked dish every time. From preparing the fresh vegetables to layering them with fragrant herbs and cheese, our video makes the cooking process even easier to follow. Watch below to master this wholesome vegetarian bake:

Why You’ll Love This Tomato & Squash Casserole

There are countless reasons why this layered Tomato and Squash Casserole quickly becomes a family favorite and a go-to recipe. Its simplicity combined with its incredible depth of flavor makes it a standout dish, whether you’re a seasoned cook or just starting your culinary journey.

• Vibrant Flavor Profile: The combination of naturally sweet tomatoes, mild squash, aromatic fresh oregano, and savory Parmesan cheese creates a harmonious blend that’s both refreshing and deeply satisfying. Each bite offers a delightful balance of earthy and bright notes.
• Nutrient-Rich Goodness: Packed with fresh vegetables, this casserole is a powerhouse of vitamins, minerals, and fiber. Zucchini and yellow squash are low in calories but rich in antioxidants, while tomatoes contribute lycopene for heart health. It’s a truly healthy vegetarian meal or side dish.
• Effortless Preparation: With straightforward slicing and simple layering, this recipe requires minimal fuss. It’s perfect for busy weeknights when you want a homemade, wholesome meal without spending hours in the kitchen.
• Incredibly Versatile: This dish shines as a vibrant side alongside grilled chicken, fish, or your favorite main course. It can also stand alone as a light vegetarian entrée when paired with a fresh salad and crusty bread.
• Seasonal Celebration: When summer gardens are overflowing with zucchini, yellow squash, and ripe tomatoes, this casserole offers the perfect opportunity to showcase their fresh, peak-season flavor. It captures the essence of late summer and early fall in every delicious spoonful.
• Crowd-Pleasing Appeal: Its beautiful presentation and universally appealing flavors make it an excellent choice for potlucks, family gatherings, or holiday meals. Even picky eaters are often won over by its gentle flavors and appealing textures.

From its ease of preparation to its delightful taste and nutritional benefits, this Tomato and Squash Casserole is a dish you’ll want to make again and again.

Essential Ingredients for Your Tomato & Squash Casserole

Gathering fresh, high-quality ingredients is key to the success of this vibrant casserole. Each component plays a vital role in building the layers of flavor and texture that make this dish so special. Here’s what you’ll need, along with tips for selecting the best produce:

• Yellow squash: Look for firm, bright yellow squash without blemishes. They offer a slightly sweeter, milder flavor and a beautiful golden hue.
• Zucchini: Choose firm, dark green zucchini. Avoid any that feel soft or have wrinkled skin. Both zucchini and yellow squash provide a delightful tender texture when baked.
• Green onion: Also known as scallions, green onions add a mild, fresh onion flavor that complements the other vegetables without overpowering them.
• Fresh oregano: This herb is a star in this recipe, lending a warm, earthy, and slightly peppery aroma. Fresh oregano is highly recommended over dried for its vibrant flavor.
• Roma tomatoes: These plum-shaped tomatoes are firm, less watery, and have a rich, sweet flavor, making them ideal for slicing and layering in casseroles as they hold their shape well.
• Olive oil: A good quality extra virgin olive oil enhances the overall flavor and helps the vegetables caramelize slightly as they bake.
• Parmesan cheese: Freshly grated Parmesan cheese adds a salty, nutty, umami depth that brings all the flavors together. Using block Parmesan and grating it yourself yields the best taste and texture.
• Garlic cloves: Freshly minced garlic provides an essential aromatic foundation for the casserole.
• Freshly ground black pepper: Adds a subtle kick and enhances the overall seasoning.
• Salt: Essential for seasoning the vegetables and drawing out their natural flavors.
• Non-stick spray: To ensure your delicious casserole doesn’t stick to the baking dish.

For precise measurements, refer to the detailed recipe card below.

Step-by-Step Guide: How to Make Tomato & Squash Casserole

Creating this layered Tomato and Squash Casserole is a straightforward process that yields impressive results. Follow these simple steps for a perfectly baked, flavorful dish:

Step 1: Prepare Your Aromatics and Cheese Mixture. Begin by thoroughly washing all your fresh vegetables. Next, mince the garlic cloves finely and chop the green onions and fresh oregano. Combine these fragrant ingredients in a medium-sized bowl with the shredded Parmesan cheese. Gently toss to ensure everything is well mixed, then set this aromatic cheese blend aside for later use (1, 2).

Step 2: Slice and Season the Squash. Carefully slice the zucchini and yellow squash into uniform rounds, approximately ¼ inch thick. Consistency in thickness is key for even cooking. Place the sliced squash in a large bowl and toss them generously with salt and freshly ground black pepper. This initial seasoning enhances their natural flavors (3).

Step 3: Prepare the Tomatoes. Slice the Roma tomatoes into similar ¼-inch thick rounds. Keep them separate from the squash for now (4).

Step 4: Begin 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 thoroughly with non-stick cooking spray. Arrange half of the seasoned zucchini and yellow squash slices in a single, even layer at the bottom of the prepared dish (5).

Step 5: Add Tomato and Cheese Layers. Neatly layer half of the sliced Roma tomatoes over the squash, creating a beautiful vibrant layer (6). Evenly sprinkle half of your reserved Parmesan cheese and herb mixture over the tomatoes (7).

Step 6: Repeat Layers and Finish. Repeat the layering process once more with the remaining squash, tomatoes, and the rest of the Parmesan cheese mixture. Once all layers are in place, lightly drizzle the top of the casserole with 1 tablespoon of olive oil. If desired, you can add a final sprinkle of extra salt and pepper for enhanced flavor (8).

Step 7: Bake to Perfection. Place the baking dish in the preheated oven and bake for 30 minutes, or until the vegetables are tender, and the cheese is melted and lightly golden brown. The edges should be bubbly and aromatic.

Step 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 allows the flavors to meld and the casserole to set, making it easier to serve clean slices.

Serve this wholesome Tomato and Squash Casserole as a delightful side dish or a light main course. Enjoy the fresh, vibrant flavors!

Expert Tips for a Perfect Squash Casserole

Achieving the best results with your Tomato and Squash Casserole is easy with a few simple tips:

• Uniform Slicing: Ensure your zucchini, yellow squash, and tomatoes are sliced to an even thickness (around ¼ inch). This guarantees that all vegetables cook at the same rate and become tender simultaneously, preventing some pieces from being undercooked or overcooked. A mandoline slicer can be very helpful for achieving perfectly uniform slices quickly and safely.
• Don’t Skip the Seasoning Between Layers: While the recipe mentions seasoning the squash, don’t be shy about adding a little salt and pepper to each layer of vegetables and even a light sprinkle over the cheese mixture. Layered seasoning builds depth of flavor throughout the casserole.
• Prevent Watery Casserole: Squash and tomatoes can release a lot of moisture during baking, which can make your casserole watery. A good tip is to lightly salt the sliced squash and tomatoes and let them sit for 15-20 minutes on a paper towel-lined baking sheet. This draws out excess water, which you can then blot away before layering. This step is optional but highly recommended if you prefer a firmer casserole.
• Choosing Fresh Herbs: Fresh oregano makes a significant difference in this recipe. Its pungent, peppery notes are much more vibrant than dried. If you can’t find fresh, use about 1 teaspoon of dried oregano for every tablespoon of fresh, but be aware the flavor will be less intense.
• Making Herb Chopping Easier: To easily chop fresh herbs like oregano, stack the leaves, roll them tightly into a cigar shape, and then thinly slice across the roll. This method yields finely minced herbs quickly and efficiently.
• High-Quality Parmesan: Opt for a block of Parmesan cheese and grate it yourself just before mixing. Pre-grated cheeses often contain anti-caking agents that can affect texture and flavor. Freshly grated Parmesan melts beautifully and provides a superior taste.
• Baking Dish Selection: A shallow baking dish (like a 9×13 inch) is ideal for this layered casserole. It allows the heat to circulate evenly, ensuring the vegetables cook through and the cheese gets nicely golden and bubbly.
• Resting Time is Crucial: Allowing the casserole to rest for 10 minutes after baking isn’t just about cooling. It gives the internal temperature a chance to equalize, helps the layers set, and prevents the casserole from falling apart when you serve it.

This layered squash and tomato bake is the perfect recipe for squash and tomato season, and it’s a great excuse to start an herb garden.

I like to keep fresh herbs growing all year, either in a planter outside during the warmer months or on a south-facing windowsill inside when the weather turns cold. For almost the same price as a single packet of fresh-cut herbs from the grocery store, you can buy a live herb plant that will produce aromatic leaves for weeks or even months, providing a continuous supply of fresh flavor for your cooking.

Substitutions & Creative Variations

This versatile Tomato and Squash Casserole is naturally vegetarian and gluten-free, making it a wonderful dish for many dietary preferences. However, it’s also incredibly adaptable, allowing for numerous substitutions and creative variations to suit your taste or what you have on hand:

Dietary Adaptations:

• Vegan & Dairy-Free: To make this recipe completely vegan or dairy-free, simply omit the Parmesan cheese. Alternatively, you can use a high-quality dairy-free Parmesan alternative. Nutritional yeast can also be sprinkled between layers for a cheesy, umami flavor.

Adding Protein:

• Make it a Main Dish: To transform this hearty side dish into a more substantial main course, consider adding a protein layer. Sautéed diced chicken breast, ground turkey, or Italian sausage (cooked and crumbled) can be layered between the vegetables. For a plant-based protein boost, add cooked lentils, chickpeas, or crumbled firm tofu (sautéed until golden).

Vegetable Swaps:

• Other Summer Veggies: Feel free to experiment with other summer vegetables. Thinly sliced eggplant, bell peppers (red, yellow, or orange), or even thinly sliced onions would make excellent additions or substitutions for some of the squash.
• Herbs: While oregano is fantastic, fresh basil or thyme would also be delicious, offering slightly different aromatic profiles. A combination of Italian herbs could also be used.

Cheese Choices:

• Different Cheeses: If you don’t have Parmesan, or simply want to try something new, experiment with other cheeses. Fresh mozzarella (sliced or shredded) melts beautifully and adds a creamy texture. Feta cheese crumbles would introduce a tangy, salty contrast, while a blend of Italian cheeses (like provolone and mozzarella) would also be delicious.

Spice & Flavor Enhancements:

• A Touch of Heat: For those who enjoy a little spice, sprinkle a pinch of red pepper flakes over the vegetable layers.
• Smoky Flavor: A dash of smoked paprika can add a subtle smoky depth.
• Citrus Brightness: A squeeze of fresh lemon juice over the finished casserole before serving can brighten all the flavors.

Don’t hesitate to get creative with this recipe. It’s a forgiving dish that welcomes personal touches!

Storage, Reheating, and Freezing

Proper storage ensures you can enjoy your delicious Tomato and Squash Casserole for days to come. Here’s how to keep it fresh and flavorful:

• Storage: Store any leftover casserole in an airtight container in the refrigerator for up to 4 days. This helps maintain its freshness and prevents it from absorbing other odors in the fridge.
• Reheating: For best results, reheat individual portions in the microwave until warmed through. If reheating a larger portion, you can place it back in an oven-safe dish, cover it loosely with foil, and bake at 350°F (175°C) for 15-20 minutes, or until heated through. The foil helps prevent the top from drying out.
• Freezing: While technically possible, this casserole isn’t ideal for freezing. Squash and tomatoes have high water content, and upon thawing, they can become quite watery and mushy, altering the texture significantly. If you must freeze it, bake the casserole completely, let it 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 and reheat as described above, being prepared for a softer texture.

Recipe Card: Tomato and Squash Casserole

Conclusion: Your New Favorite Vegetable Bake

This Tomato and Squash Casserole is more than just a recipe; it’s an invitation to savor the simple pleasures of fresh, wholesome food. With its ease of preparation, beautiful layered presentation, and comforting flavors, it’s destined to become a staple in your kitchen. Whether you’re looking for a vibrant side dish, a light vegetarian meal, or a way to make the most of your summer garden harvest, this bake delivers on all fronts. Enjoy the delightful blend of tender squash, juicy tomatoes, fragrant oregano, and savory Parmesan, bringing a touch of sunshine and homemade goodness to every meal.