Preppy Kitchen Recipes Side Dishes Cauliflower Gratin

Cauliflower Gratin

Name: Cauliflower Gratin
Prep time: 10 min
Cook time: 50 min
Total time: 60 min
Ingredients: Salt (to taste); 1 large head cauliflower (cut into florets (about 3 pounds/1.35kg)); 5 tablespoons unsalted butter (divided); 2 tablespoons all-purpose flour; 2 cups whole milk (warmed); 1¼ cups freshly shredded gruyere cheese (divided (140g)); ½ cup freshly grated parmesan cheese ((40g)); ½ teaspoon ground black pepper; ¼ teaspoon grated nutmeg; ½ cup fresh bread crumbs* ((30g))

By John Kanell Published Oct 26, 2023
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If you’re looking for a new cheesy side dish, try this cauliflower gratin recipe! Tender cauliflower is baked in a rich, creamy cheese sauce topped with crisp toasted breadcrumbs. It’s so cozy and comforting, perfect for the holidays.

A plate of cauliflower gratin with a baking dish in the background.

When I need to add a vegetable to my holiday table or Thanksgiving dinner but want to dress it up so all my guests can’t get enough, I turn to this easy cauliflower gratin. Simply boil cauliflower florets, make an easy, creamy cheese sauce, and top with toasted breadcrumbs. Trust me, even the “veggie-haters” in your life will be wanting more and more of this cheese cauliflower bake!

The cheese sauce is what makes this casserole so special. Technically called a mornay sauce, it is basically béchamel sauce with cheese added to it. I have some substitutes for the Gruyere cheese called for in the recipe, which work well in a pinch, but the best flavor comes from Gruyere, so I highly recommend it. For more holiday casseroles, try my easy squash casserole recipe, classic green bean casserole, and broccoli casserole recipe.

What You Need to Make this Recipe

Ingredients needed to make cauliflower gratin.

Cauliflower — you need a head of cauliflower cut into florets. Choose a bigger head of cauliflower (you need 3 pounds of florets!) that is firm with no soft or brown spots.

Butter — butter is an important part of the rich cheese sauce, and you also use it to toast the bread crumbs. Olive oil isn’t a good substitute for this recipe.

Flour — regular all-purpose flour is all you need. If you want to make this dish gluten-free, just use your favorite gluten-free all-purpose flour.

Milk — I use whole milk, but you could swap it for 2% milk if you like, or use half and half for a richer sauce.

Cheese — to make the mornay sauce, you’ll need to grate Gruyere and parmesan cheese. Instead of gruyere cheese, you can use another melty cheese like American Swiss cheese, sharp cheddar cheese, fontina cheese, or gouda cheese, but the flavor will be different.

Spices — black pepper and nutmeg add warmth and cozy flavor to the cauliflower cheese.

Bread crumbs — bread crumbs form a crunchy topping for the cauliflower bake. If you’re gluten-free, use gluten-free bread crumbs or gluten-free panko breadcrumbs.

How to Make Cauliflower Gratin

Set of two photos showing cauliflower added to a pot of water and flour added to a saucepan.

1. Add the cauliflower florets to a large pot of generously salted boiling water. Boil for about 10 minutes or just until fork tender. The cauliflower should still be firm. Drain well and set aside for now.

2. Make the cheese sauce in a medium saucepan. Melt butter over medium heat, then add the all-purpose flour and cook, stirring constantly, for 2 minutes.

Set of two photos showing milk and shredded cheese added to the saucepan.

3. Slowly whisk in the warmed milk until smooth. Bring the mixture to a boil while whisking. Then remove the saucepan from the heat.

4. Stir in 1 cup shredded gruyere cheese and grated parmesan cheese. Stir until the cheese has melted and the sauce is smooth. Add the black pepper, grated nutmeg, and salt to taste.

Set of two photos showing cauliflower added to a baking dish and topped with the cheese sauce.

5. Spoon about ½ cup of cheese sauce into a casserole dish and spread it so it covers the bottom of the dish. Top with the drained cooked cauliflower.

6. Pour the remaining sauce over the cauliflower.

Set of two photos showing shredded cheese added to the top of the mixture in the baking dish and bread crumbs toasted in a skillet.

7. Sprinkle the rest of the shredded gruyere cheese over the top. Bake the cauliflower casserole for 20 minutes in an oven preheated to 375°F.

8. While the cauliflower au gratin is in the oven, toast the breadcrumbs. Melt 2 tablespoons of butter in a small skillet and then add the breadcrumbs. Cook, stirring frequently, until the crumbs start to toast and brown. Remove from the heat. After the cauliflower cheese bake has been in the oven for 20 minutes, carefully remove it from the oven and sprinkle the breadcrumbs on top. Pop it back into the oven until the top starts to brown and the filling is bubbly. This will only take about 5 minutes. Allow it to cool for 15 minutes before serving to allow the sauce to thicken up. Enjoy!

A white baking dish of cauliflower gratin with a serving scooped out onto the plate in the background. Shredded cheese on a board in the back.

Pro Tips for Making this Recipe

Don’t overcook the cauliflower, and drain it well. Boil the cauliflower just until it is fork-tender but still has some firmness to it. It needs to still have a bit of bite when you bake it, or it will turn into watery mush. When draining it, I like to use a colander and let the cauliflower sit for a few minutes to remove as much water as possible.
Shred the cheese yourself instead of buying the pre-shredded kind. Pre-shredded cheese has anti-clumping agents added to it, so it isn’t as melty and gooey.
Use freshly grated nutmeg if possible. Freshly grated nutmeg has a far superior flavor to pre-grated nutmeg in this cauliflower au gratin recipe.
Add more flavor to the mornay sauce. Grated garlic cloves, garlic powder, or fresh chopped herbs would be a nice addition to the creamy cheese sauce.
To make fresh breadcrumbs: Tear one or two slices of bread (I love crusty sourdough!) and pulse in a food processor until finely chopped. You can also finely chop it with a sharp knife. If you don’t have fresh bread, panko bread crumbs can also be used.

A plate with a serving of cauliflower gratin with a baking dish in the background along with a glass of wine.

Frequently Asked Questions

Can you make it ahead of time?

Yes, you can make it ahead of time! Prepare the casserole as directed but don’t bake it. Once you sprinkle the cheese on top, allow it to cool, cover it tightly in plastic wrap, and refrigerate for up to 48 hours. When you’re ready, uncover and bake it as directed, toast the breadcrumbs, sprinkle them on top after 20 minutes, and then bake an additional 5 or so minutes until golden brown and bubbly.

What to serve with it

Cauliflower gratin is a fantastic lighter holiday side next to an entree like easy turkey meatloaf, Thanksgiving roasted turkey, or oven-roasted chicken. I like to pair it with a hearty roasted vegetable salad or crunchy shaved Brussels sprout salad.

How to store leftovers

Once the cheesy cauliflower bake has cooled to room temperature, you can either cover the baking dish well in plastic wrap and refrigerate, or transfer it to an airtight container and refrigerate. It will keep for up to 5 days.

Can you freeze it?

While you can technically freeze this cauliflower gratin recipe in a freezer-safe container, I don’t recommend it. The texture of both the cheese sauce and the cauliflower will be compromised in the freezer.

If you’ve tried this cauliflower gratin recipe, then don’t forget to rate the recipe and let me know how you got on in the comments below, I love hearing from you!