HEAT oven to 350°F.
PREPARE cake batter as directed on package for the light or low-fat version; set aside. Mix cream cheese, egg and sugar until well blended.
RESERVE 3/4 cup of the cherry pie filling for garnish. Spoon 2 Tbsp. cake batter into each of 24 paper-lined muffin cups. Top each with 1 Tbsp. each of the cream cheese mixture and remaining cherry pie filling. Cover with remaining cake batter.
BAKE 20 to 25 min. or until toothpick inserted in centres comes out clean. Cool 5 min.; remove from pan to wire racks. Cool completely. Top with Cool Whip and reserved cherry pie filling just before serving.