PREHEAT oven to 350°F. Prepare cake batter as directed on package; set aside. Mix cream cheese, egg and sugar until well blended.
REMOVE 3/4 cup of the pie filling for garnish; set aside. Spoon 2 Tbsp. of the cake batter into each of 24 paper-lined medium muffin cups. Top each with 1 Tbsp. each of the cream cheese mixture and remaining pie filling. Cover evenly with remaining cake batter.
BAKE 20 to 25 min. or until toothpick inserted in centers comes out clean. Cool 5 min.; remove from pans to wire racks. Cool completely. Top cupcakes with whipped topping and remaining pie filling just before serving.