HEAT oven to 400ºF.
PREPARE Dinner in large saucepan as directed on package except do not add the Bread Crumb Topping. Add egg, sour cream and 3/4 cup shredded cheese to macaroni mixture; mix well.
SPOON into 12 muffin pan cups sprayed with cooking spray; sprinkle with remaining shredded cheese and bread crumb topping.
BAKE 13 to 15 min. or until golden brown. Cool 5 min. before removing from pan to serve.