Sunday Baked Vegetable Casserole

Name: Sunday Baked Vegetable Casserole
Prep time: 20 min
Cook time: 40 min
Total time: 1 h
Yield: 6 servings
Ingredients: 2 cups mixed bell peppers, diced; 1 cup zucchini, sliced; 1 cup yellow squash, sliced; 1 cup mushrooms, chopped; 1 onion, diced; 3 cloves garlic, minced; 2 cups spinach, fresh; 1 can diced tomatoes (14.5 oz); 1 cup ricotta cheese; 1 cup mozzarella cheese, shredded; 1/2 cup Parmesan cheese, grated; 1 tablespoon olive oil; 1 teaspoon Italian seasoning; Salt and pepper to taste

Highlighted under: Healthy & Light

I love to prepare this Sunday Baked Vegetable Casserole as a comforting meal to share with family and friends. It's the perfect dish for a lazy weekend, packed with colorful vegetables and rich flavors. Each bite is a celebration of seasonal produce, and it always brings smiles to the table. I find that roasting the vegetables before layering them helps deepen the flavors, making this casserole a true standout. Plus, it’s versatile; you can easily adjust the ingredients based on what you have on hand.

Created by

Lila Morgan

Last updated on 2026-01-12T00:19:15.198Z

When I first set out to create this casserole, I knew I wanted to highlight the natural flavors of the vegetables rather than overpower them. Roasting them before adding to the casserole was a game changer, allowing their sweetness to shine through. Each layer of ingredients melds beautifully, creating a hearty dish that never fails to impress.

I also discovered that using a combination of fresh herbs and a hint of cheese elevates the casserole without making it too rich. The balance of flavors is key, and my family can’t get enough of it during our Sunday gatherings!

        Why You Will Love This Recipe
        A delightful mix of seasonal vegetables
Comforting and hearty for family gatherings
Versatile and adaptable to what you have in your pantry

      

Perfect Roasting for Flavor

Roasting the vegetables is a key step in developing flavor for this casserole. The high temperature of 375°F (190°C) allows the natural sugars in the vegetables to caramelize, enhancing their sweetness and depth. When roasting, make sure to arrange the vegetables in a single layer to ensure even cooking. Watch for a slight char; this means you're getting great flavor! If you notice any vegetables starting to brown too quickly, simply rotate the baking sheet halfway through the roasting process.

Each vegetable plays a specific role in the dish. For example, bell peppers provide a sweet contrast, while zucchini and squash offer a satisfying texture. The mushrooms add umami, and the onions give a savory base. If you're short on any of these vegetables, consider substituting with ones like eggplant or asparagus, which will work nicely in a similar way. Just keep in mind that different vegetables may have varying cooking times, so adjust accordingly.

Cheese Layering: The Secret to Creaminess

The cheese layers not only add richness but also support the structure of the casserole. Ricotta cheese is particularly valuable here; it provides creaminess and a light texture that balances the denser vegetables. I like to dollop it in small amounts rather than spreading it in one layer; this way, every bite carries a bit of that cheesy goodness. If you're looking for a lighter option, cottage cheese can be a great substitute, providing similar creaminess with fewer calories.

In addition to mozzarella's gooey meltability, the addition of Parmesan on top offers a deliciously salty finish. When sprinkled right before the final baking stage, it can create a beautifully golden crust that contrasts nicely with the soft vegetable layers. For a dairy-free option, consider using plant-based cheeses that melt well or leave the cheese out altogether and incorporate nutritional yeast for a nutty flavor.

Ingredients

Vegetable Casserole Ingredients

2 cups mixed bell peppers, diced
1 cup zucchini, sliced
1 cup yellow squash, sliced
1 cup mushrooms, chopped
1 onion, diced
3 cloves garlic, minced
2 cups spinach, fresh
1 can diced tomatoes (14.5 oz)
1 cup ricotta cheese
1 cup mozzarella cheese, shredded
1/2 cup Parmesan cheese, grated
1 tablespoon olive oil
1 teaspoon Italian seasoning
Salt and pepper to taste

Preparation Instructions

Instructions

Preheat the Oven

Preheat your oven to 375°F (190°C).

Prepare the Vegetables

In a large mixing bowl, combine the bell peppers, zucchini, yellow squash, mushrooms, and onion. Drizzle with olive oil, season with Italian seasoning, salt, and pepper, then toss to coat.

Roast the Vegetables

Spread the vegetable mixture on a baking sheet and roast in the preheated oven for about 20 minutes, or until they are tender and slightly caramelized.

Layer the Casserole

In a greased 9x13 inch baking dish, layer half of the roasted vegetables. Spread the ricotta cheese over the vegetables, followed by half of the spinach and half of the diced tomatoes. Repeat the layers, finishing with the tomatoes on top.

Add Cheese

Sprinkle the mozzarella and Parmesan cheese evenly over the casserole.

Bake

Cover the baking dish with foil and bake for 20 minutes. Remove the foil and bake for an additional 15-20 minutes, or until the cheese is bubbly and golden.

Serve

Allow the casserole to cool for a few minutes before serving. Enjoy your Sunday Baked Vegetable Casserole with family and friends!

Enjoy!

Pro Tips

For a gluten-free option, this casserole is naturally gluten-free, just ensure your cheese is free from any added gluten. You can also experiment with different vegetables based on the season or personal preference.

Make-Ahead and Storage Tips

This casserole is an excellent dish to prepare in advance. You can assemble the layers the night before and store it in the refrigerator, covered with foil. Just remember to remove it from the fridge about 30 minutes before baking to allow it to come closer to room temperature, which promotes even cooking. Alternatively, you can roast the vegetables a day ahead and store them in an airtight container to save time on the day of serving.

Leftover casserole can be stored in the refrigerator for up to three days. To reheat, place it in a preheated oven at 350°F (175°C) for 20-25 minutes. Cover it with foil to prevent the top from browning too much while warming through. If you’d like to freeze the casserole, I recommend freezing it before baking. Wrap it tightly and store it for up to three months. When you’re ready to enjoy it, thaw it overnight in the fridge and bake as directed.

Serving Suggestions

This Baked Vegetable Casserole pairs wonderfully with a crisp green salad or crusty bread, making it a fulfilling meal for family gatherings. You can also serve it with a light vinaigrette to enhance the freshness of the vegetables if desired. Alternatively, consider pairing it with a roasted protein such as chicken or fish for a heartier meal option.

For an Italian twist, serve this dish with a side of marinara sauce for drizzling, adding an extra layer of flavor and moisture. If you want a bit of spice, a sprinkle of red pepper flakes over the top before serving can elevate the dish and cater to those who enjoy a kick. This casserole can easily adapt to suit different cuisines based on your side choices—just let your pantry inspire you!

Questions About Recipes

→ Can I make this casserole ahead of time?

Yes! You can prepare the casserole, cover it, and refrigerate it for up to 24 hours before baking.

→ What can I substitute for ricotta cheese?

You can use cottage cheese or Greek yogurt as a substitute for ricotta.

→ Can I freeze the leftover casserole?

Absolutely! Once cooled, transfer to an airtight container and freeze for up to 2 months. To reheat, thaw overnight in the fridge and bake until warmed through.

→ What other vegetables can I add?

Feel free to include any vegetables you like! Broccoli, asparagus, or eggplant also work well.