Spoon frosting into medium bowl. Stir in powdered sugar and desired food color, mixing to blend completely. Fit an open star tip (#18) on a pastry bag, and fill with frosting. On each cupcake, pipe 6 lines from the center of the cupcake, out to the edge, making an evenly spaced "spoke-like pattern" on each. With the same tip, start in the center and make a loop by going down one side of each spoke, turning at the edge of the cupcake and following the next spoke back into the center. Repeat ending with 6 loops. Place black gummy raspberry in center of each cupcake.