There’s something irresistibly warm and satisfying about a cheesy vegetable bake, and this Broccoli Cauliflower Casserole with Cheddar and Parmesan Cheese Recipe perfectly hits that cozy comfort food spot. Creamy, cheesy, and topped with a golden crunchy crust, it’s an easy side that always gets compliments at my table.

The image shows a white square baking dish filled with a broccoli and cheese casserole topped with a golden brown breadcrumb layer. A black spatula with a wooden handle is lifting a portion from the dish, revealing bright green broccoli and soft white cauliflower pieces covered in creamy melted cheese under the crunchy crumb topping. The casserole surface is textured with a crunchy, toasted breadcrumb layer that covers the entire dish. The background and surface have a white marbled texture, and a soft white cloth is partly visible behind the dish. photo taken with an iphone --ar 2:3 --v 7

Jump to:

Why You'll Love This Recipe
Ingredients & Why They Work
Make It Your Way
Step-by-Step: How I Make Broccoli Cauliflower Casserole with Cheddar and Parmesan Cheese Recipe
Top Tip
How to Serve Broccoli Cauliflower Casserole with Cheddar and Parmesan Cheese Recipe
Make Ahead and Storage
Frequently Asked Questions:
Final Thoughts
Broccoli Cauliflower Casserole with Cheddar and Parmesan Cheese Recipe

Why You'll Love This Recipe

I often make this casserole when I want a side dish that’s both veggie-packed and indulgent without a ton of fuss. It’s one of those recipes I happily recommend because it’s easy to prep, reheats beautifully, and always pleases even picky eaters.

Simplicity meets flavor: The combo of broccoli, cauliflower, and two kinds of cheese makes every bite flavorful but straightforward.
Creamy texture with a crunchy topping: That buttery breadcrumb crust brings the perfect contrast to the soft veggies and rich sauce.
Make ahead friendly: You can prep this casserole a day or two ahead and just bake when ready, making hosting a breeze.
Versatile and crowd-pleasing: Whether for holiday dinners or weeknight sides, it fits nearly any menu.

A close-up view shows a fork holding a bite of macaroni and cheese with a crispy, golden crumb topping and tiny green herb leaves scattered on it. The macaroni is creamy yellow with a crunchy golden layer on top. The bite is lifted over a white plate with a ridged edge, where the same dish with broccoli pieces and the crumb topping is visible. The background has a white marbled texture with blurred parts of the casserole dish and some green herbs. Photo taken with an iphone --ar 2:3 --v 7

Ingredients & Why They Work

This recipe uses simple, fresh ingredients that combine to make a creamy, cheesy, and comforting casserole. Each component plays a role in creating that classic casserole texture and flavor, so having the right basics makes a huge difference.

Flat lay of fresh broccoli florets cut into 1-inch pieces, fresh cauliflower florets cut into 1-inch pieces, a small white ceramic bowl of diced raw onions, a small white ceramic bowl with peeled garlic cloves minced finely, a small white ceramic bowl of small yellow butter cubes, a small white ceramic bowl containing all-purpose flour, a small white ceramic bowl of whole milk, fresh thyme sprigs, a small white ceramic bowl of coarse salt, a small white ceramic bowl of whole black peppercorns, a small white ceramic bowl filled with shredded sharp cheddar cheese, a small white ceramic bowl with shredded parmesan cheese, a small white ceramic bowl of plain bread crumbs, a small white ceramic bowl with garlic powder, and a small white ceramic bowl with melted butter, all arranged symmetrically with realistic proportions placed on a clean white marble surface, soft natural light, photo taken with an iPhone, professional food photography style, fresh ingredients, white ceramic bowls, no bottles, no duplicates, no utensils, no packaging --ar 2:3 --v 7 --p awthu7i m7354615311229779997

Broccoli: Fresh broccoli is key for that vibrant crunch and flavor; cutting into roughly 1-inch pieces helps it cook evenly.
Cauliflower: Adds a mild, slightly nutty flavor that balances the broccoli’s earthiness and provides subtle sweetness.
Butter: Used both to sauté aromatics and bind the breadcrumb topping, it adds richness and helps flavors meld.
Onion & Garlic: These aromatics build depth in the creamy sauce; sauté until soft and fragrant for the best results.
All-purpose flour: Helps thicken the sauce to a creamy, luscious consistency that clings to the veggies.
Milk: The base of the sauce; using whole or 2% milk gives the right creaminess without heaviness.
Fresh thyme: Adds a subtle herbal note that complements the cheeses and veggies perfectly.
Salt & Pepper: Essential for seasoning and bringing all the flavors together.
Sharp cheddar cheese: Gives the casserole its signature cheesy tang and creaminess.
Parmesan cheese: Adds a nutty, savory depth that elevates the overall flavor profile.
Bread crumbs: For the topping — they get golden and crunchy, providing delightful texture contrast.
Garlic powder: Boosts the flavor of the breadcrumb topping for an extra punch of garlicky goodness.

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Note: You'll find the complete list of ingredients, along with their exact measurements, in the printable recipe card at the bottom of this post.

Make It Your Way

I love tweaking this Broccoli Cauliflower Casserole with Cheddar and Parmesan Cheese Recipe to suit different occasions or tastes, and you’ll find it’s super flexible. Feel free to swap cheeses, add proteins, or experiment with herbs to make it truly your own.

Variation: Once, I added crispy bacon bits on top and stirred in some diced ham into the sauce—it turned the side dish into a hearty main that my family adored.
Dairy-Free Version: Using vegan cheese and a plant-based milk substitute works surprisingly well if you want to accommodate dietary restrictions.
Herb Swap: Try rosemary or sage instead of thyme for a different herbal note that pairs beautifully with the cheese blend.
Extra Veggies: Toss in some diced carrots or peas for color and added sweetness—you might just start loving veggies a bit more.

Step-by-Step: How I Make Broccoli Cauliflower Casserole with Cheddar and Parmesan Cheese Recipe

Step 1: Prep and Par-Cook Your Veggies

Start by washing your broccoli and cauliflower thoroughly, then cut them into bite-sized, roughly 1-inch pieces so they cook evenly. Bring a large pot of water to a boil, then blanch the florets for about 4-5 minutes—just enough so they’re tender but still have a little snap. Drain well and transfer them to a lightly greased 9×13 inch baking dish. I find steaming works great too if you’re watching water content.

Step 2: Cook the Aromatic Base

In a large skillet, melt the butter and sauté the diced onion and minced garlic over medium heat until they turn translucent and fragrant—about 4 to 5 minutes. This step fills your kitchen with wonderful scents and really boosts the flavor of your creamy sauce.

Step 3: Build the Creamy Cheese Sauce

Sprinkle the flour over the softened onions and garlic and stir constantly to form a thick paste, which takes about a minute. Slowly whisk in the milk a little at a time, making sure the mixture stays smooth and lump-free. Keep stirring until it thickens to a velvety sauce—then season with salt, pepper, and fresh thyme. Pour this luscious sauce evenly over your prepped broccoli and cauliflower. The cheese magic happens next!

Step 4: Add Cheeses and Crumb Topping

Sprinkle the sharp cheddar and parmesan cheeses evenly over the saucy veggies. Then, mix together the plain bread crumbs, garlic powder, and melted butter in a small bowl until crumbs are evenly coated. Pat this mixture gently over the casserole's surface. This topping crisps up beautifully and adds that unforgettable crunchy texture.

Step 5: Bake to Golden Perfection

Pop the casserole into your preheated 350°F oven and bake 15-20 minutes. You’re aiming for bubbly sauce and a golden brown, crispy topping. Let it rest for a few minutes before serving—this helps the sauce thicken slightly and makes scooping easier.

Top Tip

Over the years, I learned a few little tricks that guarantee this casserole turns out perfectly every time—especially that nice balance between creamy and crunchy that makes it so addictive.

Don’t overcook your veggies: Blanching until just tender keeps the broccoli and cauliflower from turning mushy after baking.
Make a smooth sauce: Whisk constantly when adding the milk to avoid lumps—this ensures a silky texture that coats every bite.
Use fresh thyme: Fresh herbs really brighten up the casserole more than dried, but if you only have dried, just use a little less.
Watch your topping: If it’s browning too fast, loosely cover with foil for the last few minutes to prevent burning while the casserole finishes baking.

How to Serve Broccoli Cauliflower Casserole with Cheddar and Parmesan Cheese Recipe

broccoli cauliflower casserole - Serving Suggestion

Garnishes

I usually finish this casserole with a sprinkle of fresh parsley or finely chopped chives. The subtle green not only adds a pop of color but also a fresh brightness that contrasts the rich cheese beautifully. Sometimes, a small drizzle of good olive oil or a touch of paprika on top adds some warmth and appeal.

Side Dishes

This casserole pairs wonderfully with roast chicken or turkey and mashed potatoes for a classic comfort meal. I’ve also served it alongside grilled sausages or a simple pan-seared fish for a weeknight dinner that feels special but totally manageable.

Creative Ways to Present

For special occasions, I’ve served this casserole in individual ramekins topped with toasted breadcrumbs and fresh herbs. It feels a little fancy and guests love the single portions—plus, everyone enjoys getting their own cheesy, bubbly ramekin fresh from the oven.

Make Ahead and Storage

Storing Leftovers

After enjoying dinner, I store leftover casserole in an airtight container in the fridge. It keeps well for up to 3 days, and I’ve found the flavors even deepen a bit overnight—just cover it tightly to prevent it drying out.

Freezing

This casserole freezes nicely before baking or after it’s cooled post-baking. I usually freeze it pre-baked in a freezer-safe dish, then thaw overnight in the fridge when I’m ready to bake. This way, it stays fresh and creamy when baked from frozen.

Reheating

To warm leftovers, I cover the dish with foil and reheat at 350°F for about 15-20 minutes until heated through and bubbly again. If you want the topping crispy, remove the foil in the last 5 minutes of reheating.

Frequently Asked Questions:

Can I use frozen broccoli and cauliflower for this casserole?

While fresh broccoli and cauliflower give the best texture, you can use frozen if necessary. Just be sure to thaw and drain thoroughly to avoid excess water making the casserole watery.

Can this casserole be made vegan or dairy-free?

Absolutely! Substitute vegan plant-based cheeses and use a non-dairy milk like oat or almond milk. You might want to add a bit of nutritional yeast for that cheesy flavor, and use vegan butter or olive oil in the roux and topping.

What can I serve with Broccoli Cauliflower Casserole?

It pairs well with a variety of mains including roast chicken, baked ham, grilled sausage, or even a hearty lentil loaf for vegetarians. Adding a fresh green salad keeps the meal balanced and light.

How do I prevent the topping from burning?

If your breadcrumb topping is browning too quickly, loosely cover the casserole with foil for part of the baking time to shield it. You can also tent with foil once it reaches your desired crispness to avoid over-browning.

Final Thoughts

This Broccoli Cauliflower Casserole with Cheddar and Parmesan Cheese Recipe is one of those trusty dishes I go back to again and again, whether it's holiday season or just a cozy weeknight in. It’s simple, satisfying, and adaptable—a real friend in the kitchen when you want comfort without complicated steps. I hope you enjoy making it as much as I do, and it becomes a regular hit at your table too!