Mashed Cauliflower Gratin Casserole Recipe

Cauliflower casserole with melted cheese
elena_hramowa / Getty Images
Total Time: 60 min
Prep Time: 25 min
Cook Time: 35 min
Servings: 10 (1/2 cup each)

Nutrition Highlights (per serving)

132 calories
10g fat
3g carbs
8g protein
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Nutrition Facts
Servings: 10 (1/2 cup each)
Amount per serving  
Calories 132
% Daily Value*
Total Fat 10g 13%
Saturated Fat 6g 30%
Cholesterol 78mg 26%
Sodium 171mg 7%
Total Carbohydrate 3g 1%
Dietary Fiber 1g 4%
Total Sugars 1g  
Includes 0g Added Sugars 0%
Protein 8g  
Vitamin D 0mcg 0%
Calcium 189mg 15%
Iron 1mg 6%
Potassium 214mg 5%
*The % Daily Value (DV) tells you how much a nutrient in a food serving contributes to a daily diet. 2,000 calorie a day is used for general nutrition advice.

Whether as part of the holiday dinner table or enjoyed on cold winter's night, potato gratin is a welcome and comforting side dish. But if you are watching your carbs or looking to increase your nutritional intake, potatoes don't really fit the bill. That's where mashed cauliflower gratin comes in—you will still savor the creamy, cheesy goodness while getting the health benefits of cauliflower. Cauliflower has significantly fewer calories and carbohydrates than potatoes, along with a little more fiber. Some of your guests may not even be able to tell you made the swap from potatoes to cauliflower since the flavors and consistency are so similar.


  • 1 medium head​ ​cauliflower, chopped or cut into florets
  • 1/4 cup heavy cream
  • 1 tablespoon butter
  • 1 tablespoon prepared mustard
  • 1/8 teaspoon nutmeg
  • 3 eggs
  • 1 1/2 cups Gruyere cheese


  1. Preheat oven to 350 F.

  2. Cook the cauliflower until fork-tender—either microwave, covered, with a small amount of water, or steam on the stovetop.

  3. Blend cauliflower with the cream, butter, salt, pepper, mustard, nutmeg, and instant potatoes if using. An emersion blender works well, but you can also use a regular blender or food processor. (If you use a regular blender, let the mixture cool somewhat before blending. Warm ingredients are fine, but a hot mixture has the tendency to "explode" when blended with a lid on.)

  4. Add eggs and blend. Mix or blend in 3/4 of the cheese.

  5. Pour into a casserole or gratin dish, and sprinkle with the remaining cup cheese.

  6. Bake 30 to 40 minutes, until top is golden brown. The exact time will vary by the shape of the baking dish.

Ingredient Variations and Substitutions

You can add a few tablespoons of instant mashed potatoes—it's optional but they will help thicken the mixture by adding a little bit of starch. And although the name may not make them sound like they'd be natural and nutritious, instant mashed potatoes are actually dehydrated cooked potatoes, so they supply protein and fiber and are a good source of B vitamins and vitamin C.

The amount of butter and cream you will need varies slightly with the individual cauliflower, as the exact amount and moisture content varies. (You can use a large head of cauliflower—just add an egg and a little more of the other ingredients to achieve a creamy consistency.) Also, milk can be substituted for a less-rich casserole, with slightly more carbs.

Cooking and Serving Tips

This recipe is essentially a mashed cauliflower with the addition of eggs, cheese, and a little nutmeg, baked in a casserole or gratin dish. If you add an extra egg, it becomes more custard-like and puffs a bit more. This can be made ahead and baked before serving; if cold, it will take 15 to 20 extra minutes to cook.

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