Cauliflower Au Gratin

Cauliflower Au Gratin is a great way to get your family to eat more veggies.  Tender, roasted cauliflower in cheesy sauce – what’s not to love?  This dish is great for holidays too!

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Yellow baking dish of cauliflower au gratin garnished with chopped parsley.

I like to serve cauliflower au gratin with Lemon Herb Roasted Chicken, Tangy Green Bean And Potato Salad, and Sunny Lemon Cheese Tartlets for a meal that is full of bright, fresh flavors.

Cauliflower Au Gratin

I believe, at least for me anyway, that anything covered in cheese sauce tastes amazing.  This recipe makes a healthy amount of cheese sauce because I believe that you can never have too much of this sauce.

It has a ton of flavor from the roasted garlic, sauteed onion, two kinds of cheese, and some hot sauce for kick.  Try cauliflower au gratin with a baked ham or roast chicken.  It’s insanely delicious! I also make this dish as part of Christmas dinner and it’s always a hit.

Ingredients Needed

  • Cauliflower – I like using fresh cauliflower and cut the florets into big, round pieces, but you can definitely use fresh and it’ll be equally delicious.
  • Olive oil or vegetable oil
  • Salt and white pepper – you can also use black pepper
  • Garlic and onion
  • Butter, whole milk, and heavy cream 
  • Cheddar cheese and Parmesan cheese – grate your own for the creamiest sauce.
  • Flour for thickening
  • Hot sauce – add as much or as little as you want.  If you use a lot of it, your sauce will take on a more orange color.  You could also use cayenne pepper instead of hot sauce.
  • Fresh parsley for garnish

Yellow baking dish of cauliflower au gratin garnished with chopped parsley.

How To Make This Recipe

  • Cut up the cauliflower and toss it with olive oil, salt, and pepper then roast it in the oven until tender and a little golden on the top.
  • At the same time, cut the top off of the head of garlic, drizzle with oil.  Then wrap it in foil and roast alongside the cauliflower.
  • Next, make the sauce.  Saute the onions in butter and add the flour to make a roux.
  • Whisk in the milk and cream until smooth.
  • Mash the roasted garlic and stir into the sauce.
  • Add the cheese to the sauce and whisk it all together.
  • Toss the cauliflower and cheese sauce together before pouring all of this goodness into a casserole dish and bake until golden and bubbly.

Delicious Variations

  • Add some broccoli along with the cauliflower 
  • Cook some chopped bacon and use the fat to saute the onion and make the roux.  Use the crispy bacon as a topping.
  • Vary the cheeses – gruyere, Swiss, provolone, fontina, or asiago are all wonderfully delicious options.
  • Instead of heavy cream, try sour cream or cream cheese for a tangy kick.
  • Make a crunchy topping by combining one tablespoon of butter and ½ cup of cracker crumbs or panko bread crumbs and sprinkle over the top of the cauliflower and cheese before baking.

Yellow baking dish of cauliflower au gratin garnished with chopped parsley.

What To Serve With Cauliflower Au Gratin

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Yellow baking dish of cauliflower au gratin garnished with chopped parsley.

Cauliflower Au Gratin


Cauliflower Au Gratin is a great way to get your family to eat more veggies. What’s not to love about roasted cauliflower in a cheesy sauce?



1 head of cauliflower, cut into large florets

3 tablespoons olive oil

1 teaspoon Kosher salt, divided

1 teaspoon white pepper, divided

1 head of garlic

4 tablespoons butter

½ onion, finely minced

⅓ cup all-purpose flour

2 cups whole milk

½ cup heavy cream

2 cups shredded cheddar cheese, divided

¼ cup grated parmesan cheese

Few dashes of hot sauce (to taste)

2 tablespoons coarsely chopped parsley


Preheat the oven to 425 degrees.

Butter an 8×8-inch baking pan and set it aside.

In a large bowl, toss the cauliflower with 2 tablespoons olive oil, ½ teaspoon salt. And ½ teaspoon pepper until well coated.

Arrange the cauliflower on a rimmed baking sheet.

Cut about ¼-½-inch off of the top of the head of garlic.  

Drizzle the remaining 1 tablespoon olive oil over the top and wrap the garlic in foil.

Place the packet on the baking sheet with the cauliflower.

Roast the vegetables in the oven for 30 minutes or until the cauliflower is tender and lightly browned.

When the cauliflower is tender and the garlic is roasted, remove the pan from the oven and set aside to cool.  

Meanwhile, make the sauce.

In a saucepan over medium heat, melt the butter until foamy.

Add the onion and saute until translucent – about 5 minutes.

Whisk in the flour and stir until it forms a paste.

Slowly whisk in the milk and heavy cream, whisking continuously to incorporate the milk into the roux.

When the mixture is smooth, increase the heat to medium-high and allow the mixture to simmer, stirring constantly until thickened and silky smooth – about 20 minutes.

Remove the head of roasted garlic from the foil and squeeze the garlic cloves into a small bowl.

Mash them with a fork and add to the bechamel sauce.  Stir to combine.

Stir in 1 ½ cups of cheddar cheese, the parmesan cheese, remaining ½ teaspoon of both salt and pepper, and hot sauce, and whisk until melted and the mixture is smooth.  Remove from the heat.

Add the cauliflower to a large bowl.

Pour the sauce over the cauliflower and toss gently to combine.

Spoon the cauliflower and sauce into the prepared pan and sprinkle the remaining ½ cup of shredded cheese on top.

Preheat the oven to 350 degrees.

Bake the cauliflower until bubbling and golden on the top – about 30 minutes.

Allow to rest for 5 minutes and sprinkle with parsley before serving.

  • Prep Time: 20 minutes
  • Cook Time: 50 minutes
  • Category: Side Dish
  • Method: Bake
  • Cuisine: American

Keywords: cauliflower au gratin, vegetable side dish, Thanksgiving, Christmas, cauliflower, cheese sauce, bechamel sauce, Thanksgiving recipes, Christmas recipes

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