We all know Thanksgiving is about the side dishes, and this cheesy Cauliflower Gratin is a total showstopper worthy of your Turkey Day spread. Steamed cauliflower florets are tossed in a creamy cheese sauce (a béchamel, one of the Five French Mother Sauces) made with Gruyere and Parmesan. The gratin is flavored with shallots, garlic, rosemary, and nutmeg, then baked with more cheese and crunchy breadcrumbs on top. It’s total comfort food!
What is a gratin? Gratin is derived from the French word gratiner, which means to broil. It can sometimes be written out as au gratin or gratinée. No matter the spelling, it refers to a shallow baked dish with a cheese and breadcrumb topping that is either broiled or baked until bubbly and crisp.
You can make a gratin out of practically anything. One of our favorite recipes is a baked scallop gratin (swoon!), though potato gratin (pommes dauphines) is perhaps the most popular. What we love about this cauliflower au gratin recipe is the tender texture and the way the sauce seeps into every bite. It is utterly delicious!
Ingredients For Cauliflower Gratin
- Cauliflower: The star of the show! Use fresh cauliflower cut into florets.
- Unsalted butter: The fat used to sauté the vegetables and to make the roux.
- Shallots: Adds a subtle onion flavor.
- Garlic: To add flavor.
- All-purpose flour: Flour and fat (butter) are cooked together to create a roux, which thickens the cheesy sauce of the gratin.
- Whole milk: This is the liquid added to the roux to make a cream sauce.
- Gruyere: Grated gruyere (similar to swiss cheese, but nuttier) is melted into the cream sauce and mixed with steamed cauliflower before baking.
- Parmesan cheese: Use the good stuff! Freshly grated Parmigiano Reggiano will add so much nutty flavor!
- Thyme or rosemary: You could also substitute fresh sage.
- Kosher salt: To season the dish.
- Freshly ground black pepper: To season the dish.
- Nutmeg: Adds a hint of warmth to the gratin.
- Breadcrumbs: The crunchy topping that adds tons of texture to the gratin.
- Olive oil: To mix with the breadcrumbs and get them all crispy and toasted.
- Parsley: A light, fresh garnish for serving.
Miscellaneous equipment: You’ll need a steamer (or skillet with steam basket), a medium saucepan or large pot, a spatula, a whisk, and a large rectangular baking dish, such as this 10.5 – 7.5 inch Staub Rectangular Baking Dish.
How To Make Cauliflower Gratin
- Steam the cauliflower. Preheat an oven to 400F, then spray a large rectangular baking dish with nonstick cooking spray. Place ½” – ¾” of water in a saucepan or skillet with a steamer basket on top. Bring to a boil. Place the cauliflower florets in the steam basket, reduce to medium heat, then cover and cook for 5-7 minutes. Work in batches, as needed, until all cauliflower is steamed. Drain and set aside.
- Sauté the shallots. Melt butter over medium heat, then add 2 diced shallots. Cook 3 minutes, stirring occasionally. Add chopped garlic and cook 1 minute more.
- Make the roux. Add 2 Tbsp all-purpose flour, then cook for 1-2 minutes, stirring constantly. Slowly pour in 2 cups hot whole milk, whisking the entire time. Continue whisking until there are no lumps of flour and the sauce is smooth.
- Make the cheese sauce. Add ¾ cup grated Gruyere cheese, all but 2 Tbsp of the grated Parmesan, 2 Tbsp chopped rosemary or thyme, 1 tsp Kosher salt, ¼ tsp freshly ground black pepper, and ⅛ tsp grated nutmeg. Whisk until the cheese has completely melted and the sauce is thick and smooth.
- Add the cauliflower. Place the steamed cauliflower into the prepared casserole dish, then pour the thickened sauce on top. Toss to thoroughly coat the florets with the cheese sauce.
- Make the topping. In a small bowl, combine remaining ¼ cup grated Gruyere, 2 Tbsp grated Parmigiano Reggiano, and ¼ cup breadcrumbs. Mix well, then sprinkle on top of the assembled gratin. Drizzle with 2 Tbsp olive oil.
- Cook the cauliflower au gratin. Cook for 30 minutes, or until browned and bubbly on top. Sprinkle with chopped parsley, then serve immediately.
Tips For The Best Homemade Gratin
- Use fresh head cauliflower, not frozen! Frozen vegetables tend to have more water in them, which in this recipe will lead to a thinner cream sauce.
- Grate the cheese yourself! Instead of buying packaged grated cheese, buy wedges of Gruyere and Parmigiano Reggiano, then grate them yourself. You’ll be surprised by how much more flavor freshly grated cheese can add!
- Use fresh herbs, not dried. We get it, dried herbs are always there for you, and there’s a time and a place for them. This dish is so much better with fresh herbs!
- Whole milk, not skim! If you want the cheesy cauliflower to be thick and creamy, use whole milk, not skim. It has a significantly higher fat content which makes the gratin rich and luscious.
What if I don’t have a steamer?
You can simply put the cauliflower florets directly into an inch of boiling water. Bring to a boil, then cover and reduce the temperature to medium. Check after 5 minutes to test for doneness.
Can this gratin be made in advance?
Yes! You can assemble the entire gratin, right up to adding the gruyere and parmesan bread crumbs topping, then refrigerate or freeze the entire casserole dish (see below!). When ready to serve, bake in a preheated oven per the instructions, until the top is bubbly and golden brown. You may need to add a few minutes to the cook time if the gratin is cold when it goes into a hot oven.
Can I freeze cauliflower au gratin?
Absolutely! You can make this cheesy cauliflower ahead of time, then freeze for up to 3 months. Allow to cool completely to room temperature, then wrap the baking dish in both plastic wrap and aluminum foil, trying to remove as much air as possible. When ready to cook, either thaw overnight in a refrigerator or bake from frozen, adding about 5-10 minutes to the cook time, as needed.
What other cheese can I use?
Not a fan of Gruyere? It’s one of our absolute favorites, but our kids aren’t big fans. Instead, you could use a mix of grated white cheddar cheese, Asiago cheese, or Pecorino Romano (the latter would only be a replacement for the Parmesan).
Tender cauliflower, a super creamy cheese sauce, and tons of flavor from fresh rosemary, shallots, and lots of grated Gruyere. This makes an epic holiday side dish, whether you’re hosting Thanksgiving, Christmas, or just an intimate family gathering!
If you make this Cauliflower Gratin recipe, please let us know by leaving a review and rating below!
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More side dishes to try:
- Maitake Mushrooms with ‘Nduja
- Mashed Butternut Squash with Sage
- French Green Beans with Walnut Vinaigrette
- Cinnamon Applesauce
- Roasted Golden Beets with Horseradish
Cauliflower Gratin Recipe
Equipment
Ingredients
- 2 heads cauliflower cut into florets
- 3 Tbsp unsalted butter
- 2 large shallots diced, about ¼ cup
- 2 cloves garlic finely chopped
- 2 Tbsp all-purpose flour
- 2 cups whole milk
- 1 cup Gruyere grated, divided
- ½ cup Parmigiano Reggiano grated, divided
- 2 Tbsp fresh rosmary finely chopped
- 1 tsp Kosher salt
- ¼ tsp freshly ground black pepper
- ⅛ tsp nutmeg grated
- ¼ cup breadcrumbs
- 2 Tbsp extra virgin olive oil
- Parsley for serving
Instructions
- Steam the cauliflower. Preheat an oven to 400F, then spray a large rectangular baking dish with nonstick cooking spray. Place ¾" – 1" of water in a saucepan or skillet with a steamer basket on top. Bring to a boil. Place the cauliflower florets in the steam basket, reduce to medium heat, then cover and cook for 5-7 minutes. Work in batches, as needed, until all cauliflower is steamed. Drain and set aside.
- Sauté the shallots. Melt 3 Tbsp butter over medium heat, then add 2 diced shallots. Cook 3 minutes, stirring occasionally. Add 2 cloves chopped garlic and cook 1 minute more.
- Make the roux. Add 2 Tbsp all-purpose flour, then cook for 1-2 minutes, stirring constantly. Slowly pour in 2 cups hot whole milk, whisking the entire time. Continue whisking until there are no lumps of flour and the sauce is smooth.
- Make the cheese sauce. Add ¾ cup grated Gruyere cheese, all but 2 Tbsp of the grated Parmesan, 2 Tbsp, 1 tsp Kosher salt, ¼ tsp freshly ground black pepper, and ⅛ tsp grated nutmeg. Whisk until the cheese has completely melted and the sauce is extremely smooth.
- Add the cauliflower. Place the steamed cauliflower into the prepared casserole dish, then pour the thickened sauce on top. Toss to thoroughly coat the florets with the cheese sauce.
- Make the topping. In a small bowl, combine remaining ¼ cup grated Gruyere, 2 Tbsp grated Parmigiano Reggiano, and ¼ cup breadcrumbs. Mix well, then sprinkle on top of the assembled gratin. Drizzle with 2 Tbsp olive oil.
- Cook the cauliflower au gratin. Cook for 30 minutes, or until browned and bubbly on top. Sprinkle with chopped parsley, then serve immediately.
Trying out this yummy-looking dish for Thanksgiving. Just 2 things I’ve come come across with the recipe:
– the directions in step 3 are identical to step 4
– I don’t see the oven temp anywhere in the recipe
I think i can guess well enough what to do, but other more novice cooks may not. I can’t wait wait to eat some!
Hi, thanks so much for the notes — the temperature was listed at the beginning of Step 1, but you are totally right, Steps 3 and 4 were duplicates. I removed one, so should be correct now. Hope you had a wonderful Thanksgiving! xo, Ari
This is an absolutely delicious dish. I found a huge organic cauliflower on sale the other day and used half for your Cauliflower and white bean soup, and the other half for this gratin recipe. The ingredient list scaled down well to my one-half-huge cauliflower and it was a big hit with both my 98 yo mother in law, and the youngsters. Many thanks.
Thanks so much, Robert! The topping is definitely my favorite part hah! xo, Ari