There’s something so comforting about a warm, cheesy broccoli cauliflower casserole on a chilly evening. This Broccoli Cauliflower Casserole Recipe combines fresh veggies with a creamy cheese sauce and a crispy crumb topping that’ll have everyone asking for seconds. Trust me, it’s a crowd-pleaser you’ll want to keep in your recipe rotation.

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 this broccoli cauliflower casserole dozens of times for family dinners and potlucks, and it never disappoints. It’s creamy without being heavy, loaded with fresh veggies, and topped with a golden, garlicky crumb topping that adds the perfect crunch.

Creamy Comfort: The cheese sauce is rich and velvety, coating every bite with flavor.
Simple Ingredients: You probably have most of these in your kitchen already, making it super easy to whip up.
Veggie-Packed: It’s a delicious way to get those good-for-you veggies front and center on your plate.
Make-Ahead Friendly: Prepare it up to two days in advance, then bake when you’re ready—perfect for busy days.

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

The ingredients here blend freshness and comfort perfectly. The broccoli and cauliflower add that fresh crunch and mild flavor, while the cheese brings gooey, savory richness. The crumb topping seals the deal with its satisfying crispiness.

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, crisp broccoli florets provide wonderful texture and flavor.
Cauliflower: Its subtle nuttiness complements the broccoli and soaks up the creamy sauce beautifully.
Butter: Used both in the sauce and topping to add richness and help develop flavor.
Onion: Adds a gentle sweetness and depth to the sauce when sautéed.
Garlic: Intensifies flavor with a lovely aromatic punch.
All-purpose flour: The key to thickening the creamy sauce just right.
Milk: Creates a smooth, luscious base for the cheese sauce.
Fresh thyme: Adds a subtle herbal note that brightens the dish.
Salt & black pepper: Essential for seasoning and balancing flavors.
Sharp cheddar cheese: The star cheese that delivers gooey, tangy cheesiness.
Parmesan cheese: Adds umami and a slightly nutty finish.
Plain bread crumbs: For a crunchy, golden topping that contrasts the creamy veggies.
Garlic powder: Sprinkled into the crumbs for an extra layer of flavor.

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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 how versatile this casserole is—you can easily tweak it to suit your tastes or dietary needs. Sometimes I swap in different cheeses or add a handful of cooked bacon bits for a smoky twist. Don’t hesitate to adjust it to what you love!

Variation: I've added a cup of cooked quinoa for extra protein, and it was such a tasty, hearty twist!
Dairy-Free Option: Swap the cheeses for your favorite dairy-free alternatives and use plant-based milk.
More Veggies: Feel free to add chopped carrots or peas to sneak in even more color and nutrients.
Spicy Kick: A pinch of red pepper flakes in the sauce gives it a subtle heat that wakes up the flavors.

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

Step 1: Prep and Cook the Veggies Just Right

Start by washing your broccoli and cauliflower, then cut them into roughly 1-inch pieces—that way they cook evenly. Boil or steam them for 4-5 minutes until they're just tender but still have a bit of bite. Overcooking at this stage can make the casserole mushy, so keep an eye on that texture. Once done, drain well and place them in a lightly greased 9×13 inch baking dish.

Step 2: Whip Up the Creamy Cheese Sauce

In a large skillet, melt your butter over medium heat and sauté diced onions and minced garlic until soft and fragrant—about 4-5 minutes. This builds the base of flavor. Next, sprinkle in the flour and whisk it until it forms a smooth paste, cooking it for a minute or so to eliminate the raw taste. Gradually pour in the milk, whisking constantly so the sauce stays silky. Season with salt, black pepper, and fresh thyme. Keep whisking until the sauce thickens and is nice and creamy.

Step 3: Assemble and Layer the Casserole

Pour the creamy sauce evenly over the broccoli and cauliflower in your baking dish. Then sprinkle on the sharp cheddar and parmesan cheese, covering the veggies generously for that indulgent cheesiness in every bite.

Step 4: Make the Garlic Crumb Topping

Mix together plain bread crumbs, garlic powder, and melted butter in a small bowl. Spreading this mixture evenly over the top adds a wonderful crunchy, golden finish once it bakes, giving your casserole a fantastic contrast in textures.

Step 5: Bake to Perfection

Pop your dish into a preheated 350°F oven and bake for 15-20 minutes until the topping turns a beautiful golden brown and the casserole bubbles around the edges. You’ll know it’s ready when the veggies are tender and the crust feels crispy to the touch.

Top Tip

Over the years of making this Broccoli Cauliflower Casserole Recipe, I’ve discovered a few handy tricks to get the best results every time. These tips save you from common pitfalls and help you nail the balance between creamy and crispy.

Don’t Overcook the Veggies Before Baking: They’ll continue cooking in the oven, so keep them just barely tender in the steam or boil step.
Whisk the Sauce Constantly: This prevents lumps and keeps the sauce smooth and creamy.
Use Sharp Cheddar: It melts beautifully and adds a tangy richness you don’t want to miss.
Even Crumb Coverage: Don’t skimp on the topping—it adds essential texture and flavor contrast.

How to Serve Broccoli Cauliflower Casserole Recipe

broccoli cauliflower casserole - Serving Suggestion

Garnishes

I usually sprinkle a bit of freshly chopped parsley on top right after baking. It adds a fresh pop of color and a hint of brightness that complements the richness of the casserole perfectly. Sometimes, a few thinly sliced green onions work great too, especially if you want a mild onion flavor without overpowering the dish.

Side Dishes

This casserole shines as a side for roasted chicken or baked salmon, but I also love serving it alongside a simple green salad for lighter meals. It pairs wonderfully with garlic mashed potatoes or even crusty bread to soak up any leftover cheese sauce.

Creative Ways to Present

For holiday dinners, I’ve spooned this casserole into individual ramekins and topped each one with fresh herbs and a sprinkle of extra Parmesan—making it feel extra special. It’s also great served in a shallow cast-iron skillet for that rustic vibe when friends come over.

Make Ahead and Storage

Storing Leftovers

Once cooled, I cover leftovers tightly with plastic wrap or transfer them to an airtight container and store in the fridge. They keep beautifully for up to 3 days. When reheated, the sauce softens but still holds its creaminess, making for an easy, comforting lunch or dinner.

Freezing

I’ve frozen this casserole a few times by preparing the whole dish (without baking), covering it tightly with foil, and freezing for up to 2 months. When ready, I thaw in the fridge overnight and bake as usual. The texture is surprisingly good, and it’s a huge time saver.

Reheating

For the best reheating experience, I like to warm leftovers in a 350°F oven, covered with foil to prevent drying out. It usually takes about 20 minutes, depending on portion size. To re-crisp the topping, remove the foil for the last 5 minutes of baking.

Frequently Asked Questions:

Can I use frozen broccoli and cauliflower for this recipe?

You can use frozen vegetables in a pinch, but you may need to reduce the pre-cooking time since frozen veggies are often partially cooked. Also, make sure to drain any excess water to avoid a watery casserole.

What type of cheese works best in this casserole?

Sharp cheddar cheese is perfect because it melts well and gives a nice tangy flavor. Parmesan adds an umami depth and a little saltiness, rounding out the cheesy profile.

How can I make this dish vegan or dairy-free?

You can substitute the butter with plant-based margarine and use non-dairy milk like almond or oat milk. Swap the cheddar and parmesan cheeses for dairy-free vegan cheese options. Be sure to check that your bread crumbs are vegan as well.

Can I prepare this casserole ahead of time?

Absolutely! You can assemble the casserole up to 48 hours in advance, cover it tightly, and keep it in the fridge. When ready, bake it just as directed until bubbly and golden on top.

Final Thoughts

This Broccoli Cauliflower Casserole Recipe always feels like a warm hug on a plate to me. It’s one of those dishes that’s easy enough for a weeknight but special enough for guests. I really hope you give it a try and make it your own—you’ll love how easy it is to get those fresh veggies into a comforting, cheesy meal. Can't wait to hear what you think!