Italian Vegetable Casserole

Name: Italian Vegetable Casserole
Prep time: 5 min
Cook time: 50 min
Total time: 55 min
Ingredients: 3 medium sweet potatoes; 3 medium russet potatoes; 1 large yellow or white onion; 2 small yellow squash; 1 large green bell pepper; 2 tablespoons extra virgin olive oil (divided); 1 1/2 teaspoons kosher salt (divided); 1/2 teaspoon black pepper; 1 teaspoon Italian Seasoning (divided); 1 tablespoon minced garlic (divided); 1 cup spaghetti sauce; 2 large vine-ripened tomatoes; 1/4 cup freshly grated parmesan cheese (optional)

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This Italian Vegetable Casserole is a delicious and easy way to enjoy baked vegetables. Made with hearty root vegetables, tender squash, peppers, and fresh tomatoes and seasoned with Italian seasoning, garlic, and olive oil, these baked vegetables are NEXT LEVEL!

Serve this Baked Italian Vegetable Casserole with crusty Dutch Oven Bread and a tossed Greek Salad for a hearty meatless entree, or pair the baked vegetables with Chicken Marsala or Rotisserie Chicken for a delicious side.

Baked Vegetables in blue casserole dish.

If you are looking for new ways to enjoy vegetables, this Vegetable Casserole fits the bill.

Potatoes and onions are seasoned with oregano, garlic, and olive oil and roasted until tender. Then topped with a medley of summer squash, peppers, and fresh tomatoes, turning these baked vegetables into a unique vegetable casserole that is filled with Italian flavors.

Not only is this dish healthy and economical, but it is swoon-worthy! The flavors of the vegetables married with the rich tomato sauce create a dish that makes you want to lick your plate--well, at least use a slice of homemade Italian bread to soak up the richly flavored sauce.

This simple dish is a favorite dish to prepare for company, either as a side dish or as a vegetarian entree that is hearty and always impresses.

Seriously, these Italian Baked Vegetables are seriously one of the tastiest, easiest vegetable dishes to prepare. And the flavors always impress!

Key Ingredients

Potatoes, peppers, tomatoes, and squash on counter.

Vegetables: You need about 8 cups total of vegetables for this casserole. Use any combination of potatoes, sweet potatoes, carrots, onions, yellow squash, bell peppers, or zucchini. Just keep in mind that the more root vegetables used, the heartier the dish will be.
Spaghetti Sauce: The spaghetti sauce is key to flavoring this vegetable casserole. It adds moisture and flavor. Homemade Spaghetti Sauce or jarred sauce both work great.
Fresh Tomatoes: The sliced tomatoes are optional, but roasting tomatoes add a unique sweet flavor and delicate texture to this vegetable casserole.
Olive Oil: Use extra virgin olive oil for the best flavor.
Seasonings: This vegetable casserole only needs to be seasoned with minced garlic and Italian Seasoning.
Parmesan (optional): The cheese finishes the dish with a salty, earthy finish. But feel free to omit the Parmesan cheese to keep this casserole vegan and dairy-free.

How to Make an Italian Vegetable Casserole

Wash and dry the vegetables. There is no need to peel the potatoes, as the skins are filled with nutrients.
Cut the potatoes, sweet potatoes, onions, and carrots if using into 1-inch cubes. It is important to cut the vegetables to the same size so that the vegetables cook up evenly.
In a large mixing bowl, combine the vegetables with a bit of olive oil, garlic, salt, pepper, oregano, and crushed red pepper flakes. Toss to evenly coat the root vegetables in the oil and seasonings.

Potatoes and onions in mixing bowl with seasonings.

Spread the seasoned vegetables out into a 9x13 baking dish and bake until just beginning to become tender.
Meanwhile, dice the squash, zucchini, and peppers into 1-inch chunks and place them into the same mixing bowl used to season the root vegetables. Add in a bit more oil and seasonings and toss to coat. If using fresh tomatoes, slice them into ½-inch thick slices.

Peppers and onions in mixing bowl with seasonings.

Remove the potato mixture from the oven and spread the peppers and squash mixture evenly over the potatoes and onions.
Dollop with spaghetti or marinara sauce and top with fresh sliced tomatoes, if using.
Return to the oven and bake until the vegetables are fork-tender.

Collage of 4 photos showing step by step of baking veggie casserole.

Serve with Parmesan Cheese, if desired.

Baked Italian Vegetables in blue casserole dish.

Storage and Reheating

You can store any leftovers in an airtight container for up to 5 days in the refrigerator. You can opt to reheat by individual servings in the microwave on a heat-safe plate or warm the entire casserole by baking at 350 degrees F for 20-25 minutes, or until warmed through.

I love serving the leftovers over brown rice or pasta for an easy way to stretch the leftovers into another meal. It is quite delicious.

Recipe FAQs

What other vegetables can be used in the casserole?

Other good options for vegetables for this recipe would be pattypan squash, mushrooms, parsnips, or turnips. Root vegetables, such as parsnips would need to be roasted with the potatoes, while more tender vegetables, like mushrooms, would be added with the spaghetti sauce.

Can this recipe be made without oil?

The oil will add a lot of flavor to the vegetables and help them to crisp up. However, if you are on an oil-free diet, feel free to use 2-3 tablespoons of vegetable broth instead. You will need the broth so the vegetables don't dry out.

Are fresh tomatoes necessary?

Not at all! In fact, if you don't care for roasted tomatoes, simply use the spaghetti sauce.

Is the spaghetti sauce necessary?

No! I love the flavor and the heartiness that the spaghetti sauce adds to the baked vegetables. It makes it feel more like a casserole. However, you can simply use sliced tomatoes OR omit both the tomatoes and sauce and the dish will still be delicious.

More Delicious Vegetable Recipes

If you enjoyed this simple Baked Vegetable Casserole, I would love for you to leave a comment and a 5-star review below.