There’s something so comforting about a warm, cheesy veggie bake, and this Broccoli Cauliflower Casserole Recipe hits all the right notes. It’s creamy, cheesy, and topped with a crispy breadcrumb crust that gives every bite a satisfying crunch. Trust me, once you try this, it’ll become a go-to side dish in your kitchen.

The image shows a white square baking dish filled with a casserole that has a golden brown, crumbly topping layer covering creamy, white sauce-coated broccoli and cauliflower florets underneath. A black spatula with a wooden handle is lifting a portion of the casserole, showing the thick, creamy texture of the sauce and green broccoli mixed with white cauliflower below the crunchy topping. The dish is placed on a white marbled surface with a soft white cloth in the background. 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 plenty of casseroles over the years, but this Broccoli Cauliflower Casserole Recipe always feels special. It’s a great way to get your veggies into a creamy, comforting dish without them turning mushy or boring. Plus, it’s simple enough for weeknights but elegant enough to bring to holidays.

Perfect Veggie Texture: The broccoli and cauliflower stay tender-crisp, never limp or soggy, giving the casserole a great mouthfeel.
Rich and Creamy Sauce: Thanks to the homemade creamy thyme sauce, every bite is flavorful and comforting without feeling heavy.
Crispy Topping: A buttery, garlicky breadcrumb crust adds delightful crunch that contrasts with the soft veggies.
Easy to Customize: Whether you want to throw in bacon, swap cheeses, or make it vegan-friendly, this recipe is a great base to work from.

A close-up of a fork lifting a golden brown, crispy piece of macaroni and cheese topped with small green herb leaves, showing a creamy cheesy inside with a crunchy crumb layer on top. The dish is served on a white plate with decorative edges, placed on a white marbled surface; in the background, a white baking dish filled with more of the macaroni and cheese is visible but out of focus. A sprig of fresh thyme lies on the plate beside the macaroni. Photo taken with an iphone --ar 2:3 --v 7

Ingredients & Why They Work

This casserole really shines because of simple, fresh ingredients that complement each other. The fresh broccoli and cauliflower bring texture and mild flavor, while the cheesy sauce ties everything together. When shopping, I always pick tight, firm broccoli heads and crisp cauliflower for the best results.

Flat lay of fresh broccoli florets cut into 1-inch pieces, fresh cauliflower florets cut into 1-inch pieces, diced white onion, whole uncracked brown garlic bulbs alongside minced garlic cloves, a small white ceramic bowl of golden butter cubes, a small white ceramic bowl of all-purpose flour, a small white ceramic bowl of milk, fresh thyme sprigs, a small white ceramic bowl of coarse salt, a small white ceramic bowl of whole black peppercorns, shredded sharp cheddar cheese piled neatly, shredded parmesan cheese in a small mound, a small white ceramic bowl filled with plain bread crumbs, a small white ceramic bowl containing garlic powder, a small white ceramic bowl with melted butter, all arranged symmetrically and balanced 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 florets give you the best texture; don’t skip washing and cutting into bite-sized pieces.
Cauliflower: Pairs beautifully with broccoli, offering a milder, creamy note.
Butter: Essential for sautéing and adding richness to the sauce and topping.
Onion: Adds sweetness and depth when softened.
Garlic: Gives a fragrant punch that wakes up the casserole.
All-purpose Flour: Thickens the creamy sauce perfectly; make sure to cook it a bit before adding milk.
Milk: Creates a silky base for the sauce; whole milk works best but 2% is fine too.
Fresh Thyme: Adds an herby brightness that makes the sauce taste homemade and layered.
Salt & Black Pepper: Balances flavors and livens up the dish.
Sharp Cheddar Cheese: Brings boldness and melty cheesiness throughout the casserole.
Parmesan Cheese: Adds a nutty, savory note to complement the cheddar.
Bread Crumbs: Plain crumbs get dressed up with garlic powder and butter for a golden, crunchy topping.
Garlic Powder: Boosts the flavor punch in the bread crumb topping without overpowering.

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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 Recipe depending on what I have on hand or the occasion. It’s so forgiving that small changes can totally make the dish your own.

Variation: Sometimes I add cooked bacon or pancetta for a smoky twist—it’s a family favorite and adds a nice salty crunch.
Make It Vegan: Swap the butter for olive oil or vegan margarine, use a non-dairy milk like oat or almond, and try vegan cheeses—just make sure the sauce thickens nicely.
Seasonal Spin: During fall, I throw in some roasted butternut squash cubes with the broccoli and cauliflower for a hint of sweetness and vibrant color.
Milder for Kids: Use mild cheddar or mozzarella and skip the thyme if little palates are involved; they often prefer the simplicity.

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

Step 1: Prepping the Veggies Just Right

I always start by washing and cutting the broccoli and cauliflower into roughly 1-inch pieces. This size lets the veggies cook perfectly—tender but still with a little bite. Then, I boil or steam them for about 4-5 minutes. The key here is not to overcook them — you want to avoid mushy veggies that lose that lovely snap.

Step 2: Making the Creamy Sauce Base

In a large skillet, I melt butter and gently cook diced onions and minced garlic until fragrant and soft, about 4-5 minutes. Then I sprinkle in flour and whisk it constantly to create a roux—a thick paste that’s the foundation for the sauce. Slowly adding milk while whisking helps prevent lumps and creates a silky, creamy texture. Don't forget the salt, pepper, and fresh thyme—they give the sauce complexity and flavor depth.

Step 3: Bringing It All Together

Once the veggies are drained and nestled into a greased 9x13-inch pan, I pour the creamy sauce evenly over them. Then, I scatter shredded sharp cheddar and parmesan cheese on top—it melts into the sauce, making each bite cheesy and rich.

Step 4: Topping and Baking to Perfection

The last touch is the breadcrumb topping. I mix plain breadcrumbs with garlic powder and melted butter, then sprinkle this over the casserole. Baking at 350°F for 15-20 minutes lets the topping turn golden brown and crunchy, while the casserole bubbles gently underneath. You’ll know it’s done when the edges are bubbly and you see that delicious golden crust on top.

Top Tip

From my own experience making this Broccoli Cauliflower Casserole Recipe multiple times, a few simple adjustments made all the difference in nailing that perfect creamy texture and crunchy topping.

Don't Overcook the Veggies: Slightly undercooking broccoli and cauliflower before baking keeps them from turning mushy in the casserole.
Whisk Well for a Lumps-Free Sauce: Slowly add milk while whisking continuously to avoid clumps and ensure a smooth, velvety cream sauce.
Generous Cheese Layer: Don’t skimp on the cheddar and parmesan mix—it boosts flavor and melts beautifully, holding everything together.
Breadcrumb Topping Matters: Mixing garlic powder with melted butter before tossing with crumbs ensures a golden, flavorful crust rather than a dull topping.

How to Serve Broccoli Cauliflower Casserole Recipe

broccoli cauliflower casserole - Serving Suggestion

Garnishes

I usually sprinkle some fresh chopped parsley or chives on top right before serving—it adds a fresh color pop and a bit of brightness that complements the rich casserole nicely.

Side Dishes

This casserole pairs wonderfully with roasted chicken or pork tenderloin, and a simple green salad keeps the meal balanced without stealing the show. For weeknight dinners, I love serving it alongside some crusty bread to soak up any creamy sauce on the plate.

Creative Ways to Present

For holiday dinners, I’ve served this casserole in individual ramekins with parsley garnish—everyone loves having their own personal portion. Another fun idea is to prepare it in a scalloped dish and top with toasted almonds or panko for extra crunch and a festive flair.

Make Ahead and Storage

Storing Leftovers

I store leftovers in an airtight container in the fridge, and the casserole keeps well for up to three days. When reheating, I usually cover it with foil to prevent the topping from drying out and warm it up in the oven for that fresh-baked texture.

Freezing

This recipe freezes surprisingly well. I freeze it before baking, tightly wrapped in foil with plastic wrap over the top. When ready to eat, I thaw it overnight in the fridge and bake as usual—adding a few extra minutes if needed to get that bubbly, golden crust.

Reheating

To reheat leftovers, I prefer the oven over the microwave. Cover with foil and bake at 350°F until heated through (about 15 minutes). For crispiness, uncover the last 5 minutes to re-crisp the breadcrumb topping.

Frequently Asked Questions:

Can I use frozen broccoli and cauliflower for this casserole?

You can use frozen vegetables, but make sure to thaw and drain them well to avoid excess moisture that can make the casserole soggy. For the best texture, fresh is preferred.

How do I prevent the casserole from being watery?

Cooking the vegetables just until tender-crisp before baking helps reduce excess moisture. Also, make sure to whisk the sauce thoroughly and use the right ratio of flour to milk to get a thick cream sauce. Avoid adding broth if you want a thicker topping.

Can I make this casserole ahead of time?

Yes! You can prepare the casserole up to 48 hours in advance. Cover and refrigerate it until ready to bake. Bake it directly from the fridge, adding a few extra minutes if needed to ensure it’s bubbly in the center.

What can I serve alongside this Broccoli Cauliflower Casserole Recipe?

It goes great with roasted meats like chicken or pork, simple green salads, or even mashed potatoes. Crusty bread is also a nice accompaniment to soak up the creamy sauce.

Final Thoughts

This Broccoli Cauliflower Casserole Recipe has become one of those dishes I reach for when I want something easy but still feel a little fancy. It’s great for family dinners but impressive enough to bring to gatherings. Once you nail the balance of creamy sauce and crispy topping, it’s pure comfort food magic. I can’t wait for you to try it—you’re going to love how simple it is to make yet so satisfying to eat.