Kosher salt, as needed, plus 1/2 teaspoon;
Vegetable oil spray;
1 large head cauliflower, cut into small florets;
3/4 cup heavy cream,
2 ounces cream cheese, cut into small pieces;
1 1/2 teaspoons Dijon mustard;
1 1/2 cups shredded sharp Cheddar cheese, plus 1/2 cup for topping the casserole;
1/4 teaspoon black pepper;
1/8 teaspoon garlic powder
Preheat the oven to 375F. Spray an 8x8 baking dish with vegetable oil spray. Bring a large pot of water to a boil, seasoning the water with salt. Cook the cut cauliflower in the boiling water until crisp-tender, about 5 minutes. Drain well and pat between several layers of paper towels to dry. (Helpful Hints: To save on paper towels, you can place the cauliflower in a colander and drain the excess water by pressing down on the florets with a heavy bowl.) Transfer the cauliflower to the baking dish and set aside.
Bring the cream to a simmer in a small saucepan and then whisk in the cream cheese and mustard, continuously whisking until smooth. Stir in the 1 1/2 cups of cheese, salt, pepper, and garlic powder, and whisk just until the cheese melts, about 2 minutes.
Remove the sauce from the heat, pour over the cauliflower, and stir all to combine. Top with the remaining 1/2 cup cheese and bake until browned and bubbly hot, about 15 to 20 minutes. Let cool 5 minutes before serving. Serves 8.
Source: George Stella's Still Livin' Low Carb; A lifetime of Low Carb Recipes by George Stella.