- 2 heads cauliflower, cored and cut into florets
- 2 tablespoons butter, or as needed
- 1 tablespoon all-purpose flour
- 1/2 cup chicken stock
- 1/4 cup half-and-half
- 1/4 cup shredded Parmesan cheese, divided
- 1/4 cup shredded mozzarella cheese, divided
- 1/4 cup snipped fresh chives
- 1/2 teaspoon salt, or to taste
- 1/4 teaspoon ground black pepper, or to taste
- 1 pinch ground nutmeg (optional)
- 1 pinch red pepper flakes (optional)
- Place a steamer insert into a saucepan and fill with water to just below the bottom of the steamer. Bring water to a boil. Add cauliflower florets, cover, and steam until very tender, about 15 minutes. Transfer cauliflower to a plate.
- Preheat oven to 425 degrees F (220 degrees C). Butter a baking dish.
- Melt 2 tablespoons butter in a saucepan over low heat. Whisk in flour until paste forms, about 1 minute. Whisk in chicken stock and cook until thickened, about 1 minute more. Add steamed cauliflower; whip with hand mixer or immersion blender until smooth, 1 to 2 minutes. Remove from heat; stir in half-and-half, all but 1 tablespoon of the Parmesan cheese, all but 1 tablespoon of the mozzarella cheese, chives, salt, and pepper.
- Pour cauliflower mixture into prepared baking dish. Top with remaining Parmesan cheese, remaining mozzarella cheese, nutmeg, and red pepper flakes.
- Bake in preheated oven until golden brown, about 12 minutes.