Vegetable Casserole

If you’re looking for the ultimate vegetarian comfort food, this vegetable casserole recipe checks all the boxes. It’s packed with tender broccoli and cauliflower and layered with a rich, creamy sauce that’s topped with a blend of melty mozzarella and sharp cheddar. It’s the kind of dish that’s hearty enough to be the star of a meatless meal, yet versatile enough to work as a crowd-pleasing side. Best of all, it’s simple to prepare—perfect for weeknights, holidays, or potlucks.

Why I Love This Veggie Casserole

I’ve made a lot of veggie casseroles over the years—some for family dinners, others for big holiday gatherings—and this one has become my gold standard. I love how it has the perfect balance: rich and cheesy enough to feel indulgent, but still loaded with fresh, wholesome vegetables. It’s proof that comfort food doesn’t have to mean skipping your veggies!

This is the casserole I turn to when I need something dependable, quick, and guaranteed to get everyone at the table eating their broccoli and cauliflower. Even the picky eaters in my family—yes, including the kids—go back for seconds. That’s how I know it’s a winner. The combination of mozzarella for that melty stretch and cheddar for sharp, tangy flavor makes the creamy sauce irresistible, and the vegetables stay tender without turning mushy.

Over time, I’ve learned a few tricks to make it even better, like using partially thawed vegetables for baking so they hold their texture, and using a well-seasoned cream base to make every bite pop. Whether I’m serving it alongside garlic bread or Italian cheese bread, or making it the main event on a Meatless Monday, I know it’s going to be a hit and disappear fast.

Ingredients You'll Need

• 10 oz. frozen cauliflower, thawed
• 10 oz. frozen broccoli, thawed
• 8 oz. can bean sprouts or green beans, drained
• 5 oz. cream of mushroom soup
• ½ cup mayonnaise
• 1 egg
• Salt and pepper, to taste
• 4 oz. cheddar cheese, shredded
• 4 oz. mozzarella cheese, shredded

If you have any leftover broccoli after making this recipe, you can use it to make this easy broccoli rice casserole recipe next! Or, if you're looking for something a little different, check out this artichoke casserole. They're two of my favorite vegetable casserole recipes that everyone always loves.

For something a little different, you can use a lot of the ingredients to make this vegetable lasagna with white sauce.

How To Make Vegetable Casserole

Step 1: Prep

Preheat the oven to 350°F (180°C) and grease a 9-inch baking dish with some cooking spray.

Step 2: Mix the Filling

Take out a large mixing bowl and add the mayonnaise, egg, and cream of mushroom soup to it. Whisk or beat these ingredients together until they combine into a creamy sauce.

Step 3: Assemble the Casserole

 Place half the thawed broccoli, cauliflower, and bean sprouts into the prepared baking dish. Pour half the egg mixture on top and add half the mozzarella and half the cheddar cheese on top of that. Repeat the layers again until you use all of the ingredients.

Step 4: Bake and Serve

Put the casserole with veggies in the oven and bake for about 1 hour and 10 minutes. Cool the casserole briefly before slicing and serving. Letting it rest will help the filling thicken up for clean slices. Dig in and enjoy!

Expert Tips for The Best Vegetable Casserole

• Choose vegetables that hold their shape: While you can use almost any vegetable, sturdier options like broccoli, cauliflower, carrots, green beans, Brussels sprouts, and butternut squash maintain better texture after baking. Softer vegetables—like zucchini, spinach, or mushrooms—should be lightly sautéed or steamed first to remove excess water so they don’t water down the sauce
• Steam or blanch before baking: Partially cooking denser vegetables before adding them to the casserole ensures they’re tender by the time the cheese topping is golden. About 3–4 minutes in boiling water or a quick steam in the microwave is usually enough.
• Cut vegetables into uniform sizes: Even sizing ensures every bite cooks evenly and avoids having some vegetables mushy while others are underdone. Aim for pieces about 1–1½ inches in size.
• Season every layer: Don’t rely solely on the sauce to flavor the dish. Lightly season the vegetables with salt, pepper, and herbs before mixing them in so the flavors are balanced throughout.
• Change the cheese blend: Mozzarella gives you that classic stretch, but mixing it with sharper cheeses like cheddar, Colby Jack, or even Swiss creates a more complex flavor profile. Pepper jack adds a gentle kick, and Parmesan sprinkled on top before baking gives a nutty, golden crust.
• Check the doneness by the center: The casserole is ready when the sauce is bubbling at the edges and the center is hot and set. The cheese on top should be melted and lightly golden—this usually happens in the last 5–10 minutes.
• Let it rest before serving: Give the casserole at least 5–10 minutes to cool slightly after baking. This helps the sauce thicken, so it’s easier to slice and scoop neat portions without everything running together.
• Make it ahead for busy nights: You can assemble the casserole up to 24 hours in advance and refrigerate it covered. Add 5–10 minutes to the baking time if going straight from fridge to oven.

Variations To Try

• Southwest Vegetable Casserole: Mix in black beans, corn, diced bell peppers, and a sprinkle of taco seasoning. Use a cheddar–pepper jack cheese blend and top with crushed tortilla chips for crunch.
• Mediterranean Vegetable Casserole: Add chopped sun-dried tomatoes, artichoke hearts, and Kalamata olives. Swap mozzarella for mozzarella–feta blend, and sprinkle fresh oregano or basil before serving.
• Creamy Spinach & Mushroom Casserole: Sauté fresh spinach and mushrooms in garlic butter before adding them to the mix. Use Swiss or Gruyère cheese for a rich, savory flavor.
• Broccoli Cheddar Bake: Go classic with steamed broccoli florets, sharp cheddar cheese, and a touch of Dijon mustard in the sauce to deepen the flavor.
• Loaded Baked Potato Casserole: Use cubed, roasted potatoes instead of mixed vegetables, then add steamed broccoli, cheddar cheese, and crumbled cooked bacon before baking.
• Fall Harvest Casserole: Combine roasted butternut squash, Brussels sprouts, sweet potatoes, and carrots. Add a blend of cheddar and Parmesan, and finish with toasted pecans for a seasonal twist.
• Mixed Vegetable Casserole: Add a bag of partially thawed frozen mixed vegetables to the filling. The more veggies, the better! 

FAQS About This Vegetable Casserole Recipe

What can I serve with this casserole?

It's delicious with things like this garlic bread and this Italian cheese bread to dip into the luscious cream sauce. You can also serve it with more veggies like these Texas Roadhouse green beans.

How do I store leftovers?

Store any leftovers in an airtight container in the fridge for about 3 days. To freeze, transfer the leftovers to a freezer-safe airtight container and freeze for up to 3 months. For reheating, put the leftovers in a casserole dish and bake them in the oven at 350°F for about 10-15 minutes until the cheese melts and the filling is warmed. Add more reheating time for the frozen casserole or let it thaw in the fridge overnight.

Can I make this vegetable casserole ahead of time?

Yes! Just assemble the casserole before putting the cheese on, and cover the casserole dish with a lid or plastic wrap. Refrigerate overnight, then when you're ready to serve, top it with cheese and bake.

Can I add a topping to this vegetable casserole?

Yes, you can make a crumbly topping and combine crushed Ritz cracker crumbs with some melted butter. Add it right before baking the casserole. You can also add some crispy fried onions or breadcrumbs to the top of the casserole before baking.

Can I use different fresh vegetables?

Absolutely! Any of your favorite vegetables will work great, depending on what type of casserole you want to make. This recipe makes a cauliflower broccoli casserole, but you can make a green bean casserole, zucchini casserole, or squash casserole by using those vegetables.

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