Nothing says comfort quite like a warm, cheesy dish bubbling fresh from the oven. This Broccoli Cauliflower Casserole Recipe is exactly that—a perfect blend of tender veggies, creamy sauce, and that irresistible golden crumb topping that’ll have everyone asking for seconds.

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 dish countless times for family dinners and potlucks, and every single time it’s a hit. It balances fresh vegetables with rich, creamy cheese, but doesn’t feel too heavy. Plus, the crisp and flavorful crumb topping seals the deal—it’s cozy and special all at once.

Simple Ingredient Harmony: Broccoli and cauliflower meld together beautifully in this creamy, cheesy casserole that’s more than the sum of its parts.
Flexible and Friendly: Whether you want to prep ahead or tweak flavors, this recipe adapts wonderfully to your kitchen style.
Perfect Texture Contrast: Creamy base meets crunchy breadcrumb topping, giving each bite an irresistible variety.
Ideal for Gatherings: Makes a generous casserole that pleases a crowd or provides plenty of tasty leftovers.

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

The ingredients in this Broccoli Cauliflower Casserole Recipe are straightforward but thoughtfully chosen to bring out the best flavor and texture. Fresh veggies provide that crisp-tender bite, while sharp cheddar and parmesan add depth. Using butter and flour to thicken the sauce means it's luscious without being runny. Here’s why each component earns its spot:

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 and bright, broccoli holds up well when steamed briefly, adding vibrant green color and nutrition.
Cauliflower: Slightly nutty and creamy in texture, cauliflower pairs perfectly with broccoli for balance.
Butter: Acts as the base for the creamy roux, delivering richness and flavor.
Onion: Adds sweetness and depth to the sauce when sautéed just right.
Garlic: The secret to that irresistible savory punch throughout the casserole.
Flour: Helps thicken the sauce for that creamy, velvety coating.
Milk: Provides the necessary liquid to keep the sauce smooth and luscious.
Fresh Thyme: Brings a subtle herbal note that brightens the dish beautifully.
Salt & Pepper: Enhances all the natural flavors.
Sharp Cheddar Cheese: Vibrant, melty, and flavorful – this is the heart of the cheesy goodness.
Parmesan Cheese: Adds nutty complexity and helps with that golden crust.
Bread Crumbs: Combine with garlic powder and butter for that crisp topping everyone loves.
Garlic Powder (for topping): Intensifies garlic flavor in the crust without overwhelming the creamy base.
Butter (for topping): Binds the bread crumbs, letting them brown beautifully in the oven.

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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

While I stick pretty close to this recipe, I love encouraging friends to personalize it. This Broccoli Cauliflower Casserole Recipe lends itself beautifully to little tweaks that can make all the difference depending on your mood or dietary needs.

Variation: One time, I swapped sharp cheddar for smoked gouda—talk about incredible flavor depth! It’s a great way to experiment if you love smoky tastes.
Make it vegetarian or add protein: If you want some extra oomph, cooked chicken or crispy bacon bits mix in wonderfully.
Dairy-Free Adjustment: Use a creamy cashew or plant-based milk and vegan cheese alternatives to enjoy this dish without the dairy.
Seasonal Spin: Toss in some sautéed mushrooms or fresh herbs like rosemary for a cozy fall flair.

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

Step 1: Prepping the Veggies Just Right

I start by washing the broccoli and cauliflower thoroughly, then chopping them into roughly 1-inch pieces for even cooking. Next, I bring a large pot of water to boil and lightly steam the veggies for about 4 to 5 minutes—just tender enough to take the edge off without turning mushy. Drain well and place them evenly in a lightly greased 9×13 baking dish. This step helps keep that perfect texture after baking.

Step 2: Crafting the Creamy Sauce

In a large skillet, I melt the butter over medium heat, then sauté diced onions and minced garlic until soft and fragrant—this should take about 4 to 5 minutes. I whisk in the flour to form a roux and cook briefly until it smells slightly nutty but hasn’t browned. Gradually, I whisk in the milk, making sure to keep everything smooth and clump-free. Once it thickens to a creamy texture, I add salt, pepper, and fresh thyme for that herby lift.

Step 3: Bring It All Together

Pour this luscious sauce evenly over the broccoli and cauliflower in your baking dish. Then, sprinkle the shredded sharp cheddar and parmesan cheese on top. The cheese is key—it melts into the sauce and helps create that savory, golden finish.

Step 4: The Crunchy Garlic Crumb Topping

In a separate small bowl, I mix plain bread crumbs with garlic powder and melted butter until everything is coated nicely. This mixture gets spread evenly over the casserole’s surface, adding that glorious crunchy layer we all love. Then, into the preheated 350°F oven it goes!

Step 5: Baking to Golden Perfection

Bake the casserole for 15 to 20 minutes until the top is a beautiful golden brown and the veggies are tender when pierced with a fork. The aroma filling your kitchen at this point is seriously heartwarming, and you’ll know it’s time to dig in.

Top Tip

Over years of making this dish, I’ve discovered a few key tips that really help it shine—trust me, they make the difference between good and outstanding!

Perfect Veggie Texture: Don’t overcook your broccoli and cauliflower before baking; they should be barely tender to avoid a mushy casserole.
Don't Skip Fresh Thyme: It adds an amazing subtle freshness that dried herbs just can't match.
Smooth Sauce Technique: Whisk continuously after adding milk to prevent lumps in your creamy base.
Browning the Topping: Keep an eye on your crust during these last minutes in the oven to get a perfectly golden crunch without burning.

How to Serve Broccoli Cauliflower Casserole Recipe

broccoli cauliflower casserole - Serving Suggestion

Garnishes

I like to sprinkle a little extra parmesan or chopped fresh parsley on top just before serving; it adds a pop of color and a fresh note that balances the richness perfectly.

Side Dishes

This casserole pairs beautifully with roasted chicken or turkey, simple garlic bread, or even a crisp green salad dressed lightly with lemon vinaigrette to cut through the creaminess.

Creative Ways to Present

For holiday dinners or a special gathering, try serving this casserole in individual ramekins or mini cast-iron skillets. It makes each portion feel extra special and impressive.

Make Ahead and Storage

Storing Leftovers

After cooling, I cover leftovers tightly with foil or plastic wrap and keep them in the fridge. They stay delicious for up to 3 days—just reheat gently to keep that creamy goodness intact.

Freezing

I’ve frozen this casserole a few times without issue—just assemble it fully, cover tightly with foil, and freeze for up to 2 months. When ready, thaw overnight in the fridge before baking as usual, adding a few extra minutes to the bake time.

Reheating

I reheat leftovers covered with foil in a 350°F oven until warmed through. This keeps the sauce creamy and the topping from drying out or burning. Microwave works in a pinch, but oven reheating keeps the best texture.

Frequently Asked Questions:

Can I use frozen broccoli or cauliflower instead of fresh?

While you can use frozen, fresh vegetables yield a better texture and more vibrant flavor for this casserole. If using frozen, thaw and drain excess moisture well to avoid a watery dish.

Can I make this casserole vegan?

Yes! Substitute dairy milk with plant-based alternatives like almond or oat milk, use vegan cheese substitutes, and swap butter with vegan margarine or coconut oil. Keep in mind the texture might be slightly different but still delicious.

How far in advance can I prepare the casserole?

You can assemble the casserole up to 48 hours ahead of time and keep it covered in the fridge. Bake it just before serving to keep everything fresh and bubbly.

What can I serve alongside this Broccoli Cauliflower Casserole?

It pairs wonderfully with roasted meats like chicken or turkey, fresh salads, and crusty breads. The casserole is rich and hearty, so light and crisp sides complement it beautifully.

Final Thoughts

This Broccoli Cauliflower Casserole Recipe holds a special place in my kitchen—it’s that kind of dish that brings people together, whether for a casual weeknight dinner or a holiday feast. I love how it’s simple but feels indulgent, making veggies truly appealing. Give it a try—you might just find your new favorite side!