You'll feel much better feeding your kids real mac and cheese that you've made from scratch.
Melt the butter in a medium saucepan. Blend in the flour, salt, and pepper and gradually add the milk and cheese. Cook and stir over medium heat until smooth and slightly thickened. Stir in the sour cream and the cooked noodles and continue cooking over low heat until heated through. Serve immediately or transfer to a baking dish and broil until it is lightly crisp and brown on top. Makes 4 servings.