There's something so comforting about a warm, cheesy casserole bubbling with fresh veggies. This Broccoli Cauliflower Casserole Recipe hits that cozy spot perfectly, marrying crisp-tender broccoli and cauliflower with a creamy, cheesy sauce topped with a golden, buttery crumb. It's a staple in my kitchen when I want something simple, yet special.

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

This Broccoli Cauliflower Casserole Recipe is one of those dishes that feels like a big warm hug after a long day. I love how it combines fresh veggies with a rich, cheesy sauce and a crunchy topping that keeps everyone coming back for more.

Perfectly Balanced: The veggies stay slightly crisp, while the creamy sauce wraps everything in comforting flavor.
Simple Ingredients: You likely have almost everything on hand already, making it an easy weeknight side or potluck favorite.
Customizable: Whether you want extra cheese, a different topping, or want to add protein, this recipe makes it easy.
Crowd-Pleaser: It looks beautiful on the table and tastes like you spent hours perfecting it—no one needs to know otherwise!

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

Every ingredient in this Broccoli Cauliflower Casserole Recipe plays a role in delivering the perfect harmony of flavor and texture. Here’s what makes the magic happen, plus a few tips on what to pick up when you shop.

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: Choose firm, bright green broccoli crowns for the best flavor and texture; don’t overcook or it’ll get mushy.
Cauliflower: Fresh cauliflower florets balance the broccoli with a slightly nutty flavor — go for tight, white heads without brown spots.
Butter: The base for the sauce and crumb topping — provides richness and carries the garlic and onion flavors beautifully.
Onion: Adds sweetness and depth once sautéed gently; I prefer yellow onions for their mild flavor.
Garlic: Minced fresh garlic packs a punch and smells heavenly while cooking.
Flour: Creates a roux to thicken the creamy sauce without lumps — just whisk continuously.
Milk: The liquid base for the sauce; whole milk works best for creaminess, but you can go lighter if you prefer.
Fresh Thyme: This herb adds an earthy, aromatic note that brightens the dish.
Salt and Pepper: Essential for balancing and enhancing all the flavors.
Sharp Cheddar Cheese: Brings bold, melty cheesiness — sharp adds that wonderful tang and depth.
Parmesan Cheese: Adds a nutty, salty punch in the topping and sauce.
Bread Crumbs: The crunchy topping signature — I use plain, but panko can add extra crispiness.
Garlic Powder: Mixed into the crumbs for an extra layer of garlic flavor 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

One thing I love about this Broccoli Cauliflower Casserole Recipe is how easily you can tweak it to make it your own. Whether you prefer a spicier kick or a gluten-free option, it’s totally flexible.

Variation: I often swap sharp cheddar for smoked gouda or add crumbled cooked bacon for an extra savory note — it’s a total game-changer.
Dairy-Free: Use a dairy-free butter and milk alternative, plus a vegan cheese, for a friendly twist without sacrificing creaminess.
Gluten-Free: Swap the flour for a gluten-free blend and use gluten-free breadcrumbs to keep it safe for gluten-sensitive eaters.
Extra Veggies: Sometimes I toss in chopped bell peppers or mushrooms for color and texture variety.

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

Step 1: Prep and Par-Cook Your Veggies

First, give your broccoli and cauliflower a thorough rinse, then cut them into about 1-inch pieces so they cook evenly. Bring a big pot of water to a boil and either boil or steam the veggies for around 4-5 minutes. The goal is to get them semi-tender—not mushy—because they’ll finish cooking in the oven. Drain well and spread them in a lightly greased 9x13-inch baking dish. This little step really helps avoid a watery casserole.

Step 2: Make the Creamy Cheese Sauce

While your veggies are cooking, melt the butter in a large skillet over medium heat. Toss in the diced onion and minced garlic, cooking until fragrant and soft—about 4-5 minutes. Whisk in the flour and stir continuously so it thickens without lumps, then slowly whisk in the milk until smooth and creamy. Season with salt, black pepper, and fresh thyme. This creamy sauce is the heart of the casserole, so take your time here and taste as you go!

Step 3: Assemble and Add Cheeses

Pour the luscious cream sauce evenly over your broccoli and cauliflower in the baking dish. Then sprinkle with the sharp cheddar and parmesan cheese — this combo melts beautifully and adds fantastic flavor layers.

Step 4: Make and Add the Crunchy Topping

In a small bowl, mix the plain bread crumbs with garlic powder and melted butter. Evenly spread this crumb mixture over the top of your casserole. It creates that irresistible golden crust you'll find yourself scraping from the pan!

Step 5: Bake Until Golden and Bubbling

Bake your casserole at 350°F (175°C) for 15 to 20 minutes, or until the topping is beautifully golden and the veggies are tender all the way through. Let it rest for a few minutes before serving so it sets nicely.

Top Tip

From my experience making this Broccoli Cauliflower Casserole Recipe dozens of times, nailing the texture of the veggies before baking is a game-changer. Overcooking makes the casserole soggy, and undercooking leaves it crunchy. Here are some tips that saved me:

Blanch, Don't Boil Too Long: I stick closely to 4-5 minutes for par-cooking and always test with a fork—just slightly tender, not mushy.
Drain Very Well: After boiling or steaming, drain the veggies thoroughly and even pat with paper towels if needed to remove excess moisture.
Consistent Cut Sizes: Cutting florets the same size ensures even cooking and avoids surprises in texture.
Whisk Sauce Continuously: When making the roux-based sauce, patience is key to prevent lumps and get that rich, creamy finish.

How to Serve Broccoli Cauliflower Casserole Recipe

Broccoli Cauliflower Casserole - Serving Suggestion

Garnishes

Whenever I serve this casserole, I like to scatter a few fresh thyme leaves or a sprinkle of chopped parsley on top for a pop of color and herbal brightness. Sometimes a grating of extra parmesan right before serving adds a lovely finishing touch.

Side Dishes

This casserole pairs beautifully with simple mains like roasted chicken, baked ham, or grilled salmon. For veggies, I love light options like a crisp green salad or roasted carrots to balance all that creamy goodness.

Creative Ways to Present

For special occasions, I've served this Broccoli Cauliflower Casserole Recipe in individual ramekins or mini cast iron skillets. It makes each portion look elegant and fun, plus everyone loves their personal crispy crumb top. Another fun twist is swirling in some sun-dried tomatoes or caramelized onions before baking for bursts of flavor and color.

Make Ahead and Storage

Storing Leftovers

Leftovers keep well in an airtight container in the fridge for 3-4 days. I usually reheat portions in the microwave, but to keep the crumb topping crispy, a quick oven reheat works best. Just cover loosely with foil and warm at 350°F for 10-15 minutes.

Freezing

I’ve frozen this casserole once or twice—just assemble it without baking, then wrap tightly with foil and freeze for up to 2 months. When ready, thaw overnight and bake until hot and bubbly. Keep an eye on the crumb topping; sometimes it needs a few extra minutes to crisp up after freezing.

Reheating

To bring leftovers back to life, I recommend reheating in the oven over the microwave to preserve texture. Cover the casserole loosely with foil and heat at 350°F until warmed through—about 15-20 minutes depending on portion size. If the topping has softened, you can remove the foil for the last 5 minutes to crisp it up again.

Frequently Asked Questions:

Can I use frozen broccoli and cauliflower for this casserole?

You can use frozen veggies if you're in a pinch, but I really recommend fresh broccoli and cauliflower for the best texture and flavor. If using frozen, thaw and drain thoroughly to avoid excess moisture making the casserole watery.

How do I prevent the casserole from being soggy?

Par-cooking the broccoli and cauliflower just long enough to get them semi-tender and draining them very well before baking reduces excess moisture. Also, avoid over-pouring sauce — it should coat but not drown the veggies. Using fresh ingredients and a good crumb topping helps maintain texture.

Can I make this casserole ahead of time?

Absolutely! You can prepare the entire casserole up to 48 hours in advance. Just cover it tightly and refrigerate. When ready to serve, bake until bubbly and golden, adding a few extra minutes if needed to heat through.

What can I use instead of bread crumbs for topping?

If you don't have breadcrumbs or want a gluten-free option, crushed cornflakes, crushed crackers, or panko breadcrumbs all work well. You can also try finely chopped nuts like almonds or pecans mixed with melted butter for a crunchy topping with extra flavor.

Final Thoughts

This Broccoli Cauliflower Casserole Recipe has truly earned a permanent spot in my recipe box. The way the fresh veggies, creamy sauce, and golden crumb topping come together feels like a celebration of simplicity done right. I hope you find it just as comforting and easy to make for your family gatherings or weeknight dinners. Trust me, once you try this, it’ll become one of those dishes you’ll want to make again and again — just like I do!