Preheat oven to 450 degrees F (230 degrees C). Line a baking sheet with aluminum foil.

Arrange cauliflower on the prepared baking sheet. Sprinkle with salt, mixed herbs, and pepper. Drizzle with olive oil; toss until well coated.

Roast in the preheated oven until crisp, 10 to 15 minutes. Place in an 8-inch baking dish.

Combine Cheddar cheese, heavy cream, ghee, and nutmeg in a saucepan over medium heat; simmer until bubbly, about 5 minutes. Pour over cauliflower; mix well. Sprinkle Parmesan cheese on top.

Bake in the preheated oven until golden, about 10 minutes.