Cheesy Cauliflower Casserole
Inside: The cheesy sauce that takes plain cauliflower to an au gratin casserole even the kids will love.
This cauliflower casserole is like a vegetable version of mac and cheese–and it’s wonderful. Cauliflower florets tossed into a cheesy Gruyère sauce, with a crunchy breadcrumb topping and baked until hot and bubbly. It’s creamy, cheesy and familiar — just built around a head of cauliflower instead of pasta.
This is one of those back-pocket recipes that transforms ho-hum veg into something everyone actually wants to eat. The creamy sauce is a straightforward béchamel (butter, flour, milk, with a few simple seasonings). Nutty Gruyère cheese (similar to Swiss or Emmentaler) adds richness and body to the sauce, and the crispy buttered crumb topping adds texture.
If you’re trying to get kids (or skeptical adults) to eat more veggies, this is a solid strategy.
Serve this cauliflower casserole alongside roast chicken or grilled steak, or make it the main event with a simple salad and call it dinner. It’s rich enough for holidays, easy enough for a weeknight, and a smart way to turn a humble cruciferous vegetable into something that disappears fast.
Also try these unique side-dish casseroles: Simple Scalloped Potatoes, Creamy Chayote Gratin, and Kale, Barley Mushroom Gratin.
Why this recipe works:
- Pre-steamed cauliflower–The florets are cooked until just tender (either on the stovetop or in the microwave), for a shorter bake time and perfect doneness.
- Classic béchamel for reliable creaminess. A simple roux helps thicken the cream sauce, so it clings to the florets, for a cauliflower casserole that’ll win you over.
- Cheese for the win–Gruyère cheese is known for its smooth, lush melt, and the nutty flavor has more character than cheddar (though it’s an option if you like).
- Texture in every bite–A golden brown breadcrumb topping adds a satisfying crunch.
- Flexible enough for side or main. It’s sturdy and satisfying on its own, but also plays well with roasted meats or grilled mains.
Ingredients for cheesy cauliflower casserole:
- Cauliflower–a whole head. Depending on the size, you may have a larger or smaller casserole. Though I recommend fresh cauliflower, in a pinch, use a large bag of frozen cauliflower florets.
- Butter–Used in both the white sauce and for making buttered breadcrumbs. I use unsalted butter, but salted works fine too.
- All-Purpose Flour–to make the béchamel sauce.
- Nutmeg–I recommend grating nutmeg on a microplane in lieu of ground spices; the flavor is more pronounced.
- Dry Mustard Powder–mustard powder intensifies the cheese flavor.
- Kosher Salt–I use Diamond Crystal Kosher salt, which has less sodium by volume than Morton’s. If you use Morton’s, reduce the amount by about ⅓.
- Black Pepper–Freshly ground has the most robust flavor.
- Milk–whole milk will give a richer sauce, but lowfat or skim will work as well.
- Gruyère Cheese–a nutty, semi-firm specialty cheese from Switzerland. If you can’t find it, swap it with Emmental or Swiss. You can also use other types of cheese (see the Swaps and Variations section below).
- Bread–Whatever you have on hand for fresh breadcrumbs (you can even use hot dog buns).
- Parsley–Italian flat leaf or curly parsley. No need to chop, just twist the stems off and use the leafy parts.
Step-by-step instructions:
- Cut the cauliflower into bite-sized florets, then steam them in a microwave-safe container with ¼ cup of water, covered with plastic wrap, for 4-5 minutes, or until tender. (Note: Stick one with a sharp paring knife or fork, and if the vegetable slides off on its own, it’s ready). Drain the vegetables well and set aside to let excess moisture evaporate.
2. Heat a medium saucepan over medium-high heat and melt the butter; Add the flour, mustard powder, nutmeg, kosher salt and black pepper. Whisk until the melted butter coats the other ingredients and there are no dry bits left in the pan. Cook, stirring for one minute until bubbly and fragrant.
3. Add the milk a little at a time, stirring constantly. Once the sauce is smooth and starts to thicken, add a little more milk. Continue in this fashion until all the milk has been added. Simmer at a low bubble for one minute, stirring constantly, then remove from the heat.
4. Stir in the grated Gruyère until it’s melted and the cheese sauce is smooth and creamy.
5. Fold the cauliflower florets into the cheese sauce until coated with the sauce.
6. Combine the bread, butter and parsley in a mini food processor and pulse until the parsley is chopped and the breadcrumbs are fine.
7. Spray a one-quart casserole dish with vegetable spray. Pour the cauliflower into the prepared baking dish. Spread into an even layer and top with breadcrumbs.
8. Bake at 375°F for 18-20 minutes. To give the crust a golden-brown top, broil for 1-2 minutes. Allow the cauliflower casserole to rest for about 10 minutes before serving.
Pro-Tips:
- Ensure the cauliflower is well drained, and any excess moisture is patted dry before adding it to the sauce; otherwise, you risk a watery casserole.
- Grate your own cheese; pre-shredded cheese often contains anti-caking agents that can mute the flavor.
- Let the cauliflower au gratin rest for 10 minutes after baking; this allows the sauce to thicken and prevents you from burning your tongue on the molten sauce.
- Kids may prefer cheddar cheese to Gruyere (it’s more familiar), so if you have picky eaters, make the swap.
Swaps and Variations:
- Use different cheese–You can easily make this with cheddar cheese, fontina, gouda, monterey jack cheese or other grated semi-firm cheeses. Additionally, stirring in 4 ounces of cream cheese will double-down on the creamy factor. Each variety will give the cauliflower au gratin a slightly different flavor, but all are delicious.
- Blend grated parmesan cheese with the fresh breadcrumbs for more flavor.
- Use panko instead of fresh breadcrumbs; just spritz them with some vegetable spray before baking to enhance browning.
- Add ½ cup of onion to the butter and sauté until softened before adding the flour and spices. This adds another layer of depth to the casserole.
- Use a combination of cauliflower and broccoli florets in the recipe.
- Add a cup of ham or chicken to the cauliflower au gratin to make a complete meal.
- Sprinkle the creamy cauliflower casserole with chopped bacon for extra richness.
FAQs
A cheesy sauce always enhances cruciferous veggies like cauliflower or broccoli.
Cauliflower has a lot of natural moisture, which prevents it from crisping, but the breadcrumb topping adds texture.
Because this casserole only bakes for 20 minutes, the cauliflower needs to be blanched or steamed first; it won’t become tender otherwise.
Make ahead:
- You can make the cauliflower au gratin several hours ahead and store it in the fridge; bake it off just before you want to serve it.
Storage:
- Usually, I would recommend an airtight container for storage, but in order to preserve the crunchy breadcrumb topping, I store leftovers in the same dish covered with foil in the refrigerator.
Reheating:
- Reheat at 350°F for 10-15 minutes or until hot and bubbly.
Freezing:
- I don’t recommend freezing the casserole as the cauliflower can weep liquid and make the dish watery.
More cauliflower recipes you’ll love:
Cauliflower Casserole (Au Gratin)
INGREDIENTS:
- 1 head cauliflower
- 2 ½ tablespoons unsalted butter
- 2½ tablespoons all purpose flour
- ¼ teaspoon nutmeg
- ¾ teaspoon dry mustard
- 1 teaspoon kosher salt
- ½ teaspoon black pepper
- 2 cups milk
- 1½ cups Gruyère cheese grated
FOR BREADCRUMB TOPPING:
- 2 slices bread white, wheat, rye, sourdough, etc.
- 4-5 sprigs parsley
- 1½ teaspoons butter
DIRECTIONS:
- Preheat the oven to 375°. Spray a small casserole dish with vegetable spray and set aside.
- Trim 1 head cauliflower into bite-sized florets and transfer to a microwave-safe container. Add about ¼" cup of water and cover with plastic wrap. Microwave on high for about 5 minutes or until the cauliflower is tender. See other methods in the notes below.
- In a medium saucepan, heat 2 ½ tablespoons unsalted butter over medium-high heat. When butter is melted and bubbly, whisk in 2½ tablespoons all purpose flour, ¼ teaspoon nutmeg, ¾ teaspoon dry mustard, 1 teaspoon kosher salt and ½ teaspoon black pepper. Stir until the butter and dry ingredients form a paste or roux.
- Add 2 cups milka little at a time, whisking constantly. Add more milk once the mixture thickens and bubbles. Continue in this manner until you've used all the milk and have a creamy white sauce. Cook, stirring and scraping the sides and edges until the milk mixture thickens and comes to a low boil. Cook for one minute and remove from the heat.
- Add1½ cups Gruyère cheese cheese; stir until melted. Add the drained and cooled cauliflower to the cheese mixture, then fold the florets into the sauce until coated.
- Tear 2 slices bread into pieces and transfer to a mini food processor. Add 4-5 sprigs parsley and 1½ teaspoons butter. Pulse until the bread and parsley are finely chopped.
- Spray a 1-quart baking dish with vegetable spray and spread the cauliflower mixture into an even layer in the dish. Sprinkle with about ½ cup of the buttered bread crumbs.
- Bake for 18-20 minutes, until bubbly. Turn the broiler to high and cook for 1-2 more minutes, or until the breadcrumbs are nicely browned. Remove from oven and rest for 5-10 minutes before serving.
RECIPE VIDEO:
NOTES:
- You can make the cauliflower au gratin several hours ahead and store it in the fridge; bake it off just before you want to serve it.
- Usually, I would recommend an airtight container for storage, but in order to preserve the crunchy breadcrumb topping, I store leftovers in the same dish covered with foil in the refrigerator.
- Reheat at 350°F for 10-15 minutes or until hot and bubbly.
- I don’t recommend freezing the casserole as the cauliflower can weep liquid and make the dish watery.
NUTRITION:
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This is an easy recipe with TONS of flavors. Thank you!
I LOVE mustard with cauliflower! Keep up the good work!
YUM. Holy smokes this looks and sounds amazing. You can call it a gratin. You can call it cauliflower cheese. I call it I need this in my mouth, STAT! Cauliflower is one of my favorite vegetables. I can’t wait to try this!
I’m glad you approve Christina — it doesn’t last long in this house!
Whoa! How delicious. Love how you’ve added mustard into the sauce.
This is essentially a variation on what I know more humbly as cauliflower cheese, a staple especially for kids in the UK – this is a little fancier though and love the smoked gouda. By the way try it alongside steak – a great match!
Anything with a béchamel in French is a gratin – sounds fancy, but it’s really just cauliflower cheese! LOL!
OMG, this looks amazing! I’ve always been obsessed with cauliflower and I’m so glad everyone is embracing it these days. This is total comfort food!
Thank you, Jenn! This IS comfort food… Enjoy!
I’m always on the lookout for ways I might be able to convince my husband to eat some cauliflower – smothering it in delicious cheese like this sounds like a pretty good bet! I especially love the Gouda!