Sunday Baked Vegetable Casserole

Name: Sunday Baked Vegetable Casserole
Prep time: 30 min
Cook time: 45 min
Total time: 1 h 15 min
Yield: 6 servings
Ingredients: 2 cups zucchini, sliced; 1 cup bell peppers, chopped; 1 cup spinach, chopped; 1 cup mushrooms, sliced; 1 medium onion, diced; 3 cloves garlic, minced; 2 cups shredded cheese (cheddar or mozzarella); 1 cup breadcrumbs; 1 teaspoon dried oregano; Salt and pepper to taste; 2 tablespoons olive oil; 1 can (14 oz) diced tomatoes; 1 teaspoon balsamic vinegar; 1/2 teaspoon sugar

Highlighted under: Baking & Desserts

I love preparing this Sunday Baked Vegetable Casserole for family gatherings, as it brings everyone together around the table. The vibrant colors and rich flavors of seasonal vegetables make this dish not only satisfying but also a feast for the eyes. It’s simple to assemble and can be prepped in advance, which gives me more time to enjoy the company of loved ones. The combination of melted cheese and crispy breadcrumbs on top provides a wonderful texture to the hearty filling below, making it a true comfort food on any Sunday.

Created by

Bethany Clarke

Last updated on 2026-01-13T22:52:23.970Z

When creating this casserole, I experimented with various vegetables to find the perfect balance of flavors and textures. I discovered that using zucchini, bell peppers, and spinach not only enhances the taste, but also adds a beautiful medley of colors that makes the dish visually appealing. I also love adding fresh herbs to elevate the flavor profile even further.

The key to achieving that golden-brown top lies in a mix of breadcrumbs and cheese. I find that adding a little olive oil to the breadcrumbs before baking helps them crisp up nicely, providing a delightful crunch that contrasts beautifully with the tender veggies underneath.

        Why You'll Love This Recipe
        Vibrant and colorful array of fresh vegetables
Cheesy, crispy topping that adds texture
Easily adaptable to include your favorite seasonal produce

      

Choosing the Right Vegetables

When it comes to preparing this baked vegetable casserole, selecting fresh, seasonal vegetables is essential for optimal flavor and texture. Zucchini adds a subtle sweetness, while bell peppers contribute a satisfying crunch. Spinach introduces a nutritious green element, and mushrooms bring an earthy essence that enhances the overall profile. If you're looking to mix it up, consider substituting eggplant for zucchini or adding seasonal vegetables like asparagus or broccoli for an exciting twist. Just be sure to balance the moisture content in the dish to prevent sogginess.

To ensure even cooking, cut your vegetables into uniform sizes. This not only helps them cook at the same rate but also improves the visual appeal of the dish. For bell peppers, remove the seeds and membranes, and chop into bite-sized pieces. Slicing zucchini thinly allows it to become tender while still retaining a slight bite—aim for about a quarter-inch thickness. Remember, the goal is to achieve a cohesive blend of textures in each bite.

Casserole Assembly Tips

The assembly of your casserole is just as important as the cooking process itself. Begin by spreading an even layer of the prepared tomato sauce in your baking dish, which not only prevents sticking but also infuses the bottom layer of vegetables with rich flavor. When layering the vegetables, try to distribute them evenly to ensure every portion receives a good mix. I like to reserve some cheese for the very top layer to create that irresistible gooeyness and golden topping during baking.

Be mindful not to overfill your baking dish; a 9x13 inch pan usually works well for this recipe. If you find yourself with leftover filling, consider using a smaller dish or even individual ramekins for single servings. This not only helps with portion control but also makes for a great presentation when serving guests. Additionally, using breadcrumbs on top can enhance that crunchy texture, so don’t skimp on them—feel free to use panko for extra crispiness.

Ingredients

For the Casserole

2 cups zucchini, sliced
1 cup bell peppers, chopped
1 cup spinach, chopped
1 cup mushrooms, sliced
1 medium onion, diced
3 cloves garlic, minced
2 cups shredded cheese (cheddar or mozzarella)
1 cup breadcrumbs
1 teaspoon dried oregano
Salt and pepper to taste
2 tablespoons olive oil

For the Sauce

1 can (14 oz) diced tomatoes
1 teaspoon balsamic vinegar
1/2 teaspoon sugar

Feel free to modify the vegetable mix based on what you have on hand!

Instructions

Preheat the Oven

Preheat your oven to 375°F (190°C).

Prepare the Sauce

In a saucepan, combine the diced tomatoes, balsamic vinegar, and sugar. Simmer on low for about 10 minutes.

Sauté the Vegetables

In a large skillet, heat the olive oil over medium heat. Add the onion and garlic, sautéing until translucent. Then add zucchini, bell peppers, and mushrooms; cook until softened.

Combine Ingredients

Stir in the spinach, oregano, salt, and pepper. Remove from heat and mix in half of the shredded cheese.

Assemble the Casserole

In a baking dish, spread a layer of the tomato sauce on the bottom. Add the vegetable mixture and top with the remaining sauce. Sprinkle with breadcrumbs and the rest of the cheese.

Bake

Bake for 25-30 minutes until the top is golden and bubbly.

Serve

Let the casserole cool for a few minutes before serving. Enjoy your meal!

Perfect for Sunday gatherings or as a weekday supper, this casserole can be served alone or with a side salad.

Pro Tips

For added flavor, try roasting the vegetables before adding them to the casserole. This simple step will enhance the natural sweetness and depth of flavor.

Make-Ahead and Storing

One of the great aspects of this Sunday Baked Vegetable Casserole is that it can easily be prepared ahead of time. Feel free to assemble the dish up to a day in advance, cover it tightly with plastic wrap, and store it in the refrigerator. When you’re ready to bake, remove it from the fridge and let it sit at room temperature for about 30 minutes to ensure even cooking. This saves you time on busy Sundays, allowing you to enjoy your gathering without rushing to the kitchen.

Leftovers can also be stored in an airtight container for up to three days in the refrigerator. To reheat, simply place the casserole in a preheated oven at 350°F (175°C) for about 15-20 minutes or until heated through. If you're feeling fancy, you can sprinkle a little extra cheese on top before reheating to bring back that deliciously cheesy topping.

Flavor Variations

Feel free to get creative with this recipe by experimenting with different flavor profiles. For a Mediterranean twist, consider adding feta cheese, kalamata olives, or artichoke hearts to enhance the dish's depth. You could even incorporate cooked quinoa or lentils to turn it into a heartier entree. Adding a pinch of red pepper flakes can give a delightful hint of spice, perfect for those who enjoy a little kick in their meal.

If you're looking for a way to make this casserole a bit lighter, swap out the cheese for vegan alternatives, or use nutritional yeast for a cheesy flavor while keeping it plant-based. Additionally, using whole grain breadcrumbs can provide added fiber and a nuttier taste, which pairs beautifully with the veggies. These little adjustments allow everyone to enjoy this comforting dish without compromising on their dietary preferences.

Questions About Recipes

→ Can I use frozen vegetables?

Yes, you can use frozen vegetables. Just make sure to thaw and drain them before adding to the casserole.

→ What type of cheese works best?

Cheddar and mozzarella are great options, but feel free to experiment with your favorite cheese.

→ How long does leftovers last?

Leftovers can be stored in the refrigerator for up to 3 days in an airtight container.

→ Can I make this casserole vegan?

Yes! Use plant-based cheese and breadcrumbs, and substitute those with a brown sauce or vegetable broth for a delicious vegan option.