Creamy Cauliflower Gratin

This 30-minute cauliflower gratin is rich, cheesy, and comforting. It's the perfect alternative to potato gratin!

Course Side Dish

Cuisine French

Prep Time 15

Cook Time 15

Total Time 30

Servings servings

Calories 218kcal

1 teaspoon butter for pan
1 pound cauliflower florets
1 cup sour cream
1 teaspoon Dijon mustard
1 tablespoon fresh garlic minced
½ cup Gruyere cheese grated; 50 grams
1 teaspoon Diamond Crystal kosher salt or ½ teaspoon of any other salt, including Morton kosher salt
½ teaspoon black pepper freshly ground
2 tablespoons Parmesan cheese grated

Preheat the oven to 425°F. Grease a shallow 1.5-quart baking dish with butter or olive oil.
Place the cauliflower florets in a large microwave-safe bowl. Add a tablespoon of water. Cover with a microwave-safe plate and microwave on high until tender-crisp, 5-7 minutes.
Meanwhile, in a large bowl, mix together the sour cream, mustard, garlic, gruyere, salt, and pepper.
Drain the cooked cauliflower well (be careful, the bowl will be hot) and pat it dry. Add it to the sour cream sauce, gently tossing to combine.
Transfer the mixture to the prepared baking dish. Sprinkle the parmesan on top.
Bake the gratin until heated through, for about 10 minutes. Serve immediately.

If your baking dish is broiler-safe, you can switch the oven to broil after the gratin is done and broil it for 1 minute to brown the top. Keep a close eye on it so that it doesn't burn.
To use frozen cauliflower, defrost it according to the package instructions, taking care not to overcook it, and drain it thoroughly.
You can keep the leftovers in an airtight container in the fridge for up to 4 days. Reheat them covered in the microwave at 50% power. I don't recommend freezing the leftovers.