Broccoli Cauliflower Casserole is the perfect side dish for a holiday gathering, made with broccoli and cauliflower in a creamy, cheesy sauce mixed with spices and topped with gluten free breadcrumbs for a crispy crust, ready in 45 minutes!

If you’re looking for more vegetable side dish recipes, check out my Loaded Baked Potato Casserole, Parmesan Roasted Brussel Sprouts, or Instant Pot Mashed Potatoes!

Broccoli and cauliflower in a cheesy sauce topped with breadcrumbs on a fork above the casserole dish.

Broccoli Cauliflower Casserole is the perfect dish for a family gathering any time of year, but I especially love to serve it on Thanksgiving and Christmas. You can make this dish with only broccoli, only cauliflower, or swap them out completely for other veggies like green beans. It’s really versatile! I also like to mix it up sometimes and swap half of the veggies out with cooked (al dente) gluten free pasta for a broccoli cauliflower mac and cheese!

Ingredients You’ll Need

ingredients on a table for broccoli cauliflower casserole

Broccoli and Cauliflower Florets Obviously the main ingredients for this dish. You can use all broccoli, all cauliflower, or a mix of the two. I prefer to cut up fresh head cauliflower and broccoli florets, because you’ll get the best texture that way after roasting and cooking. If you don’t have a lot of time, you can use steamed broccoli and cauliflower with the water drained.

Make sure you cook the broccoli and cauliflower beforehand, or your casserole will end up watery.

Cheddar Cheese I prefer to use sharp cheddar cheese because of personal preference. But you can use whatever type of cheese you’d like here. Try mild cheddar, Monterey jack cheese, mozzarella cheese and parmesan cheese, Swiss, or any other good melting cheese. 

The key here is to buy the block and shred it yourself. The pre-shredded cheese had additives in it that don’t do well in homemade creamy sauces.

Butter and Gluten Free Flour  Butter and flour whisked together is the key to thicken your cheese sauce. If you add more flour, you’ll get a much thicker sauce.

I use unsalted butter so I can control the flavor, but salted would work fine too. Hold back adding salt until after you have your cheese sauce made, then carefully taste some and season with salt as needed. 

Spices I kept it simple with some salt, pepper, onion powder, and paprika. You can use whatever you’d like here! 

Gluten Free Breadcrumbs The breadcrumbs mixed with butter toast in the oven and give you a crispy crust on top of the casserole, giving the perfect contrast to the cheesy creamy center! I use unseasoned breadcrumbs so I can add my own spices to them, but seasoned would work, too.

Lately I’ve been able to find gluten free panko breadcrumbs. A crunchy panko breadcrumb topping works really well for this recipe.

step by step photos for broccoli cauliflower casserole

How to Make Cheesy Broccoli Cauliflower Casserole

  1. Cut up your broccoli and cauliflower and place on a sheet pan. Roast at 400 degrees F for 20 minutes.
  2. While that’s roasting, melt butter in a saucepan over medium heat. Whisk in flour, whisking constantly until flour starts turning brown and smells nutty. Add spices.
  3. Slowly whisk in milk. Whisking often until it starts to thicken, add cheddar and stir until melted. 
  4. Grease a medium baking dish. Add broccoli and cauliflower, then pour cheese sauce over, using a spoon to mix together. 
  5. In a separate bowl, mix breadcrumbs with melted butter. Sprinkle breadcrumb mixture over the top of the casserole and bake for 15-20 minutes, or until golden brown.  

Jacqui’s Tip! If your breadcrumbs aren’t toasted as much as you’d like, turn the broiler on for a minute. Watch your casserole carefully during this, because it can burn really fast! 

Do you have to cook broccoli before putting it into a casserole?

I definitely recommend cooking broccoli before putting it into a casserole. Broccoli will release water as it cooks, so cooking it beforehand helps to prevent a watery casserole. This recipe calls for roasting the broccoli, to help it keep a lot of the texture.

Can you make broccoli and cauliflower casserole ahead of time?

Yes! You can make broccoli cauliflower casserole ahead of time. Just follow all of the directions up until just before baking. Refrigerate your casserole dish wrapped tightly with plastic wrap. When ready, remove the plastic wrap and bake the casserole until cheese is melted again and the crust is golden brown, about 20 minutes.
The cooking time can vary if the casserole starts out colder. If the top starts to get too crispy before the rest is done, carefully cover with tinfoil for the rest of the cook time.

Can I use frozen broccoli in casserole?

Yes, you can use frozen broccoli in casserole! Just keep in mind that you won’t get as much of the firm texture as you would with fresh roasted broccoli. Make sure you defrost the broccoli completely and drain it before use. You can also use a microwave steam bag and drain off all of the liquid after steaming.

Can I freeze broccoli cauliflower casserole?

I don’t recommend freezing this casserole, because the cheese sauce will not defrost well and the texture will be off.

Jacqui’s Tip! This cheesy casserole dish is a really good base to try different flavors. Just swap out the spices for Italian seasoning, curry powder, Ranch seasoning, taco seasoning, or whatever you’re in the mood for! Try adding some minced cloves garlic and fresh herbs like parsley and thyme. 

More Broccoli and Cauliflower Recipes to Try

Broccoli and cauliflower in a cheesy sauce topped with breadcrumbs on a fork above the casserole dish.

Tips and Tricks

  • Add some red pepper flakes or cayenne pepper to the cheese sauce to make this dish spicy!
  • Make this broccoli cauliflower casserole vegan by using vegan butter, unflavored almond milk, and a good melty vegan cheese. I recommend almond-based cheese for flavor. Make sure your ingredients are gluten free, as vegan food can vary.
  • Make this an all-in-one dish by adding leftover chicken when you add the cheese sauce to the veggies (make sure the chicken is fully cooked first). This is a great way to use up rotisserie chicken! Use a deep baking dish so it doesn’t overflow. The same baking dish you’d use for lasagna would work.
  • If you want to make the sauce heavier, use half milk and half heavy cream. Or try half and half instead of heavy cream for some more texture with less fat.
  • Make the loaded version by adding cooked savory bacon and green onions on top of the finished casserole. Serve with a spoonful of sour cream.
  • This recipe also works with frozen cauliflower rice, but steam it first and drain any excess water. The riced cauliflower will add a totally different texture though, more like mashed potatoes. I would add some gluten free pasta and cooked chicken to bulk it up. 

If you loved this recipe, be sure to leave a 5 Star review below, and tag me with a photo of your finished recipe on instagram @Jacqui_DishingDelish!

Broccoli and cauliflower in a cheesy sauce topped with breadcrumbs on a fork above the casserole dish.

Broccoli Cauliflower Casserole

Broccoli Cauliflower Casserole is the perfect side dish for a holiday gathering, made with broccoli and cauliflower in a creamy, cheesy sauce mixed with spices and topped with gluten free breadcrumbs for a crispy crust, ready in 45 minutes!
5 from 1 vote
Prep Time: 5 mins
Cook Time: 40 mins
Total Time: 45 mins
Course: Dinner, Side Dish
Cuisine: American
Author: Jacqui
Yield: 10 servings

Ingredients
 
 

  • 5 cups cauliflower, chopped
  • 5 cups broccoli, chopped
  • 1 medium Vidalia onion, chopped
  • 3 tablespoons unsalted butter
  • 1 1/2 tablespoons gluten free all-purpose flour
  • 1 1/2 cups 2% milk
  • 1 1/2 cups cheddar cheese, shredded
  • 1/2 teaspoon salt
  • 1/2 teaspoon black pepper
  • 1/2 teaspoon onion powder
  • 1/2 teaspoon paprika

Breadcrumb Topping

  • 1 cup gluten free breadcrumbs, plain
  • 4 tablespoons unsalted butter, melted
  • 1/2 teaspoon garlic powder
  • 1/2 teaspoon paprika

Equipment

  • 1 baking dish
  • 1 Saucepan
  • 1 baking sheet

Instructions
 

  • Preheat oven to 400°F. Line a baking sheet with parchment paper. Place broccoli, cauliflower, and onion on the baking sheet and bake for 20 minutes.
  • While the vegetables are cooking, melt 3 tablespoons of butter in a saucepan over medium heat. Add flour and whisk until flour begins to turn brown and gives a nutty aroma. Whisk in spices.
  • Add milk and whisk until mixture begins to thicken. Add cheese and stir until melted. Remove from heat and set aside.
  • Grease a large casserole dish. When vegetables are done, remove from sheet pan and add to casserole dish. Pour cheese sauce over broccoli and cauliflower and stir to mix everything together.
  • In a separate bowl stir together breadcrumbs, butter, and spices. Make sure breadcrumbs are completely wet. Sprinkle on top of casserole evenly.
  • Bake casserole uncovered for 15-20 minutes, or until topping is golden brown.

Notes

Click on the time in the instructions to start a timer!
Cheesy. Pre-shredded cheese often has trouble melting as well as the block of cheese that you shred yourself. I recommend shredding it yourself for best results. 
Substitutions.
  • Swap the broccoli and cauliflower for green beans or squash. 
  • Use heavy cream or half and half instead of milk for a richer texture. 
  • You can swap the spices for whatever you’d like. Try Ranch seasoning or taco seasoning! Or try fresh herbs like parsley or thyme.
  • Add red pepper flakes or cayenne pepper to make it spicy.
Make it Vegan
  • Swap the butter with vegan butter
  • Use plain almond milk or vegetable broth instead of milk. If you use broth, it will be more like a gravy, but still tasty!
  • Use a good melting vegan cheese. 
Storage
You can store this casserole in an airtight container in the refrigerator for 3-4 days. 
I don’t recommend freezing this dish, because the cheese sauce won’t defrost well and won’t keep a good texture.
Make Ahead
This recipe is great for making ahead of time! I would say the day before, but not much longer.
Follow all directions as written, but right after you add the breadcrumb topping set the dish aside to cool for a few minutes. Then wrap tightly and refrigerate. 
When you’re ready, just bake for about 20 minutes at 400°F, or until cheese is melted and topping is golden brown. If the top is getting too toasty, cover with tinfoil until it’s done baking (careful – it’s hot!).

Nutrition

Calories: 234kcal (12%)Carbohydrates: 18g (6%)Protein: 9g (18%)Fat: 15g (23%)Saturated Fat: 9g (56%)Polyunsaturated Fat: 1gMonounsaturated Fat: 4gTrans Fat: 0.4gCholesterol: 41mg (14%)Sodium: 278mg (12%)Potassium: 406mg (12%)Fiber: 3g (13%)Sugar: 5g (6%)Vitamin A: 834IU (17%)Vitamin C: 66mg (80%)Calcium: 206mg (21%)Iron: 1mg (6%)
Did you make this recipe?Share it on Instagram @Jacqui_DishingDelish and tag #dishingdelish!

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