Food Network has a simple and easy to follow recipe for a low-carb mac and cheese casserole that substitutes cauliflower for the macaroni. This recipe makes six servings.
To make Food Network's cauliflower "mac" and cheese casserole, preheat the oven to 375 degrees F. Bring to a boil a large pot of salted water, and cook 1 large head of cauliflower that has been cut into small florets for five minutes, or until it is crisp-tender. Drain the water, and pat cauliflower dry with paper towels. Place the cauliflower in an 8-by-8-inch baking dish greased with vegetable oil, and set aside.
In a saucepan, simmer 1 cup of heavy cream, and add 2 ounces of cream cheese and 1 1/2 teaspoons of Dijon mustard. Combine until smooth, and add 1 1/2 cups of shredded sharp cheddar, 1/4 teaspoon of freshly ground black pepper, 1/2 teaspoon of kosher salt and 1/8 teaspoon of garlic powder. Cook for one to two minutes, or until the cheese melts. Remove the saucepan from the heat, and pour the cheese mixture over the cauliflower. Mix thoroughly, top with 1/2 cup of shredded sharp cheddar, and bake for 15 minutes, or until the top is browned and bubbly.