1. Heat oven to 350°F. Line muffin cups (2-1/2 inches in diameter) with foil or paper bake cups. Prepare FILLING; set aside.
2. Beat sour cream, banana, oil, milk, eggs and vanilla in large mixer bowl until combined. Stir together flour, sugar, baking soda, baking powder and salt. Gradually add flour mixture to banana mixture, blending thoroughly. Fill muffin cups 1/2 full with batter. Place heaping tablespoon FILLING in center of batter.
3. Bake 23 to 25 minutes or until wooden pick inserted in cake portion comes out clean. Remove from pan to wire rack. Cool 5 minutes. Spread about 1 teaspoon chocolate spread or peanut butter chocolate spread over top of cupcake. Cool completely. About 24 cupcakes.
FILLING: Beat 1 package (8 oz.) softened cream cheese, 1/2 cup HERSHEY'S Spreads Chocolate or REESE'S Spreads Peanut Butter Chocolate, 1/3 cup sugar, 1 egg and 1/8 teaspoon salt in small mixer bowl until smooth and creamy.