Cauliflower au Gratin is a creamy veggie dish with roasted cauliflower in a rich cheesy sauce.

This cauliflower side dish is perfect alongside a roast dinner, and great with almost any cheese in your fridge!

cooked Cauliflower au Gratin in the dish with some taken out

What is Cauliflower au Gratin?

A gratin is a method of making a baked dish or casserole that’s covered in breadcrumbs and/or cheese and browned. We often think of Potatoes Au Gratin but it’s great for all kinds of vegetables including brussels sprouts, zucchini, spinach, and more!

In this recipe, the cauliflower is roasted (adding another layer of flavor) which keeps it from getting watery. The sauce is homemade but it’s easy to make and so rich!

Why You’ll Love This

  • Super rich and super cheesy, it tastes amazing!
  • Roasting cauliflower adds flavor while keeping it perfectly tender-crisp.
  • The cheese sauce is great with any cheese that you have on hand.
  • This dish is low carb and high in flavor.
  • This cozy dish can be made ahead of time and baked before serving.

ingredients for cauliflower au gratin

Ingredients

CAULIFLOWER: Choose a large head that is free of brown spots. Short on time? Use a fresh bag of pre-washed and pre-cut cauliflower.

This recipe does work with frozen cauliflower as well, be sure to drain it very well after cooking so the sauce doesn’t get watery.

SAUCE: This sauce uses milk in place of cream and cream cheese gives it an extra rich flavor and texture.

CHEESE: Sharp cheddar adds great flavor. I love to use a little bit of Gruyere or swiss cheese as well. If you’re not a fan of swiss cheese, use all cheddar or another type of cheese.

Variations

For a colorful vegetable au gratin, mix broccoli florets with the cauliflower or add a medley of veggies like zucchini, onions, or leeks to the roasting pan. Or add diced chunks of ham, cooked chicken, or bacon for a heartier main dish casserole.

cooked cauliflower on a baking sheet to make Cauliflower au Gratin

How to Make Cauliflower au Gratin

  1. Roast: Roast seasoned cauliflower until tender.
  2. Make Sauce: While cauliflower is roasting, make a roux & whisk in milk (per the recipe below). Cook until bubbly.

adding cheese to a dish

  1. Add Cheese: Stir in remaining ingredients (except for ¼ cup cheddar cheese). Whisk & simmer until smooth.
  2. Bake: Combine the sauce with the roasted cauliflower and bake in a casserole dish.

Cauliflower au Gratin in the casserole dish before baking

Tips for Perfect Gratin

  • Roasting the cauliflower keeps the sauce from getting watery. If you steam or boil (or use frozen) be sure to drain very well.
  • Broccoli can be added to the cauliflower if desired.
  • The sauce is very rich, ensure your cauliflower head is at least 7-8 cups.
  • Remove the sauce from the heat before stirring in the cheese. If the cheese overheats or boils it can separate.
  • The cheese on top can be replaced with buttery bread crumbs. Combine 1/3 cup breadcrumbs with 1 tablespoon melted butter and sprinkle over top before baking.

top view of cooked Cauliflower au Gratin in the dish

Storing Leftovers

Keep leftover cauliflower au gratin in a covered container in the fridge for up to 4 days.

More Cheesy Sides

Did your family love this Cauliflower au Gratin? Leave us a rating and a comment below! 

close up of cooked Cauliflower au Gratin
4.95 from 87 votes↑ Click stars to rate now!
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Cauliflower au Gratin

Cauliflower au Gratin is a creamy & cheesy side dish, baked until perfectly golden!
Prep Time 20 minutes
Cook Time 45 minutes
Total Time 1 hour 5 minutes
Servings 8 cups

Ingredients  

  • 8 cups cauliflower florets about 1 large head
  • 2 tablespoons olive oil
  • salt & pepper to taste

Sauce

  • 2 tablespoons butter
  • 2 tablespoons all-purpose flour
  • 2 cloves garlic minced, optional
  • 1 cup milk
  • 4 ounces cream cheese softened
  • ¼ teaspoon salt or to taste
  • ¼ teaspoon black pepper
  • ½ teaspoon dry mustard powder
  • 1 cup sharp cheddar cheese shredded & divided
  • ½ cup Gruyere or swiss cheese shredded, or additional cheddar

Instructions 

  • Preheat oven to 400°F.

Roast Cauliflower

  • Rinse cauliflower and break into bite-sized florets. Toss with olive oil and salt and pepper to taste.
  • Place on a baking sheet and roast 15-20 minutes or until tender.

Make Sauce

  • While cauliflower is roasting, melt butter (and garlic if using) in a saucepan until fragrant, about 30 seconds. Whisk in flour until smooth and let cook for 1 minute. Add milk a little at a time while whisking until smooth.
  • Cook over medium heat until thick and bubbly. Stir in cream cheese, salt, black pepper, and mustard powder until smooth. Add in ¾ cup cheddar cheese and swiss cheese. Whisk until smooth.

Bake

  • Toss cheese mixture with roasted cauliflower and place in a 2 qt casserole dish. Top with remaining cheese and bake 20-25 minutes or until heated through.
  • Broil 1-2 minutes or until browned.

Video

Notes

Roasting the cauliflower keeps the sauce from getting watery. If you steam or boil (or use frozen) be sure to drain very well.
Broccoli can be added to the cauliflower if desired.
The sauce is very rich, ensure your cauliflower head is at least 7-8 cups.
Remove the sauce from the heat before stirring in the cheese. If the cheese overheats or boils it can separate. 
The cheese on top can be replaced with buttery bread crumbs. Combine 1/3 cup breadcrumbs with 1 tablespoon melted butter and sprinkle over top before baking.
Leftovers can be stored in an airtight container in the refrigerator for up to 4 days.
4.95 from 87 votes

Nutrition Information

Serving: 1cup | Calories: 251 | Carbohydrates: 8g | Protein: 9g | Fat: 21g | Saturated Fat: 11g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 7g | Trans Fat: 1g | Cholesterol: 53mg | Sodium: 304mg | Potassium: 306mg | Fiber: 2g | Sugar: 4g | Vitamin A: 621IU | Vitamin C: 35mg | Calcium: 226mg | Iron: 1mg

Nutrition information provided is an estimate and will vary based on cooking methods and brands of ingredients used.

Course Side Dish
Cuisine American
cooked Cauliflower au Gratin with a spoon and a title
close up of Cauliflower au Gratin in the dish with a title
ingredients to make Cauliflower au Gratin with writing
ingredients to make Cauliflower au Gratin with cooked dish full and a title

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About the author

Holly is a wine and cheese lover, recipe creator, shopping enthusiast and self appointed foodie. Her greatest passion is creating in the kitchen and making deliciously comforting recipes for the everyday home cook!
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Comments

  1. This looks great! How do I make this ahead of time? I’m thinking of making this as a side for Christmas dinner, so would love to do as much the day before as possible. Thanks!

    1. Hi Jamie, this dish can be assembled the day before and baked the next day! I would store in the fridge overnight, then take it out and let it sit on the counter about 30-45 minutes before baking. Then bake as per the recipe! :)

  2. This sauce is divine! I was sneaking it with a spoon (I love cheese way too much). The family loved it and we all agreed I need to make a double batch next time. Tossed in a few potato chunks as well just to use up a stray potato and it worked great.5 stars

  3. This was EXCELLENT! I made the full recipe and there’s only DH and myself, so there’s lots of leftovers. Does this freeze well?

    1. I have not tried freezing, but it should work just fine! I am so happy to hear you loved this recipe Jean.

  4. I made this today and followed recipe exactly although I crushed Ritz crackers with melted butter for topping. My husband has never been fond of vegetables of any kind and he said it was delicious.. it’s a keeper recipe! Thanks!5 stars

    1. You sure can but I would suggest either steaming or boiling the cauliflower. It won’t cook enough in the sauce.