Preheat oven to 350°F. Prepare cake mix as directed on package. Remove 1 1/2 cups of the batter to medium bowl. Stir in 1 tablespoon of the raspberry flavor and red food color. Pour into greased 8-inch square baking pan. Reserve remaining batter.
Bake 12 minutes or until toothpick inserted into center comes out clean. Cool on wire rack. Cut out 12 heart shapes with 1-inch heart-shaped cookie cutter. Set aside.
Stir vanilla into reserved batter. Pour 1/2 off the batter evenly into 12 paper-lined muffin cups. Press 1 cake heart vertically into center of each muffin cup. Pour remaining batter over top. Bake 15 to 18 minutes or until top of cupcake is set. Cool cupcakes on wire rack.
Meanwhile, beat butter and remaining 2 teaspoons raspberry flavor in large bowl until light and fluffy. Gradually add confectioners' sugar alternately with cream, beating well after each addition and scraping sides and bottom of bowl frequently. Frost cooled cupcakes with frosting.