Preheat oven to 350F. Coat a 4-quart baking dish with butter cooking spray.

Cook macaroni according to package directions but without added salt and oil; drain and transfer to a large bowl. While macaroni is still hot, stir in American and cheddar cheeses; stir until cheese melts. Add milk, sour cream, mustard and nutmeg; mix well to combine.

Transfer mixture to prepared baking dish and top with grated topping. Bake until top is golden, about 30 to 35 minutes. Yields about 1 1/2 cups per serving.

http://www.weightwatchers.com/food/rcp/index.aspx?recipeId=103661