There’s something incredibly comforting about a warm, cheesy casserole bubbling fresh from the oven, and this Broccoli Cauliflower Casserole Recipe hits all the right notes. It’s creamy, flavorful, and the perfect way to turn simple veggies into a dish everyone asks for again.

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 Recipe
Top Tip
How to Serve Broccoli Cauliflower Casserole Recipe
Make Ahead and Storage
Frequently Asked Questions:
Final Thoughts
Broccoli Cauliflower Casserole Recipe

Why You'll Love This Recipe

I’ve made this Broccoli Cauliflower Casserole Recipe more times than I can count, and it never disappoints. Whether it’s a weeknight dinner side or part of a holiday spread, it brings that cozy, homemade feeling everyone loves.

Comfort in Every Bite: The creamy, cheesy sauce hugs every bit of broccoli and cauliflower, making veggies delicious for even the pickiest eaters.
Simple Ingredients: You probably have most of what you need tucked away already, so this casserole is both convenient and fuss-free.
Great Make-Ahead Dish: You can prep this casserole up to two days in advance—saving you time and stress on busy days.
Crunchy, Golden Topping: The buttery breadcrumb crust adds just the right amount of crisp contrast to the creamy veggies underneath.

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

Each ingredient in this Broccoli Cauliflower Casserole Recipe plays a role in building layers of flavor and texture. Choosing fresh veggies and sharp cheeses really makes all the 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: Opt for firm, bright green florets—this brings freshness and a slight crunch after baking.
Cauliflower: Similarly, fresh cauliflower adds a mild, nutty flavor and contrasts beautifully with broccoli.
Butter: It adds richness to the sauce and helps brown the breadcrumbs for that irresistible crisp topping.
Onion: Sautéed until soft, onion gives a savory depth that complements the creamy cheese.
Garlic: Adds a fragrant punch that will make your kitchen smell incredible and lift the whole dish.
All-purpose flour: This thickens the sauce, giving it that luscious, smooth texture.
Milk: Provides creaminess without weighing down the casserole; feel free to adjust for your preferred thickness.
Fresh Thyme: A wonderful herb that brightens the cream sauce with an earthy note.
Salt & Pepper: Essential for seasoning and bringing all ingredients together in harmony.
Sharp Cheddar Cheese: Its tangy, bold flavor makes this casserole vibrant and cheesy.
Parmesan Cheese: Adds a nutty, salty finish that rounds out the cheese blend perfectly.
Bread Crumbs: The topping’s crunch factor; plain crumbs keep the focus on the flavors beneath.
Garlic Powder: Sprinkled into the topping for an extra garlic boost without moisture.

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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 like to tweak this casserole depending on the season and who’s coming over. A few simple swaps can make it suit different dietary needs or just keep things interesting.

Variation: For a lighter casserole, I sometimes swap half the cheddar for mozzarella, which melts beautifully but is less intense.
Vegetarian Twist: Adding toasted nuts like walnuts or pecans on top before baking adds great texture and flavor without meat.
Herb Swaps: I’ve used rosemary or sage in place of thyme to change up the herbaceous notes.
Make It Gluten-Free: Use gluten-free flour and bread crumbs, and you won’t miss the wheat.

Step-by-Step: How I Make Broccoli Cauliflower Casserole Recipe

Step 1: Prep and Par-Cook Your Veggies

Start by washing and chopping your broccoli and cauliflower into bite-sized pieces—about an inch or so works best. Then, boil or steam them for 4 to 5 minutes just until they’re semi-tender. You don’t want mush here; the veggies will finish cooking in the oven. Drain well, then transfer to a lightly greased 9x13-inch baking dish. I like to line my pan with parchment underneath sometimes—it makes cleanup a breeze.

Step 2: Make the Creamy Sauce

In a large skillet, melt the butter over medium heat. Toss in your diced onions and minced garlic, cooking until everything is soft and fragrant—about 4 to 5 minutes. Whisk in the flour and cook for a minute to get rid of that raw flour taste. Next, gradually whisk in the milk, keeping it smooth and creamy. Add salt, pepper, and fresh thyme—this last touch adds such a cozy, earthy flavor. Stir until the sauce thickens nicely, then pour it over the veggies in your baking dish.

Step 3: Cheese It Up and Top It Off

Sprinkle the shredded sharp cheddar and parmesan cheeses evenly over the creamy veggies. In a small bowl, mix together the bread crumbs, melted butter, and garlic powder. This topping is the secret to that satisfying crunch. Spread it evenly on top to prepare for baking.

Step 4: Bake Until Golden and Bubbling

Bake your casserole in a preheated 350°F oven for 15 to 20 minutes. You’re looking for a bubbly center and a golden, crisp topping. It’s worth keeping an eye on it toward the end because that buttery breadcrumb crust can brown quickly. Once your kitchen smells like cheesy heaven, it’s ready to come out.

Top Tip

This Broccoli Cauliflower Casserole Recipe has been a go-to for me because of its forgiving nature—here are a few things I’ve learned to get it just right every time.

Don’t Overcook Your Veggies: Pre-cooking just until tender-crisp keeps the casserole from turning soggy while baking.
Whisk the Sauce Properly: Gradually adding milk and whisking constantly prevents lumps in your creamy sauce.
Butter Your Breadcrumbs Well: Melted butter mixed in the crumbs helps them brown evenly instead of drying out.
Let It Rest a Bit: I usually let the casserole cool for 5-10 minutes before serving so the sauce thickens perfectly and it’s easier to serve.

How to Serve Broccoli Cauliflower Casserole Recipe

broccoli cauliflower casserole - Serving Suggestion

Garnishes

I like to sprinkle a little fresh parsley on top just before serving—it brightens up the richness and adds a pop of color. A few crispy fried onions can also be fun for extra crunch and depth on special occasions.

Side Dishes

This casserole pairs wonderfully with roast chicken or a juicy pork tenderloin. For vegetarian meals, I enjoy serving it alongside a crisp salad or herbed quinoa to keep things light but satisfying.

Creative Ways to Present

For holiday dinners, I sometimes bake individual portions in ramekins, topped with a dash of smoked paprika for a festive touch. It makes the presentation feel extra special and keeps everyone’s serving neat and tidy.

Make Ahead and Storage

Storing Leftovers

I store leftovers tightly covered in the fridge—they usually last 3 to 4 days. Reheating in the oven keeps the topping crisp better than the microwave, which can sometimes make it soggy.

Freezing

I've frozen this casserole before, though for best texture, I recommend freezing before baking. Thaw overnight and then bake as usual; this way, the crumb topping stays crisp and delicious.

Reheating

To reheat, cover loosely with foil and warm in a 350°F oven for about 15 minutes, or until heated through. If you want to refresh the topping, I remove the foil for the last 5 minutes to bring back that crunch.

Frequently Asked Questions:

Can I use frozen broccoli and cauliflower for this casserole?

Yes, you can use frozen broccoli and cauliflower to save time. Just thaw and drain them well before cooking to avoid excess moisture that can make the casserole watery.

How do I make this casserole gluten-free?

Simply substitute the all-purpose flour with gluten-free flour (like a rice or almond flour blend) and use gluten-free bread crumbs for the topping. The texture might be slightly different but still delicious!

Can I add other vegetables to this dish?

Absolutely! Carrots, peas, or even mushrooms can be great additions. Just make sure to adjust cooking times for any veggies that need longer to soften.

What’s the best way to get a crunchy topping?

Mixing melted butter into the bread crumbs and sprinkling garlic powder as in the recipe is key. Also, bake uncovered and watch for the topping to turn a lovely golden brown without burning.

Final Thoughts

This Broccoli Cauliflower Casserole Recipe is one of those dishes that feels like a warm hug in food form—simple ingredients, straightforward steps, and a result that’s downright satisfying. I hope you find as much joy in making and sharing it as I do. Trust me, once you’ve got this on your table, it’ll quickly become a classic for your family, too.