Preheat oven to 350 degrees.
Prepare a cupcake pan with liners.
Spritz with nonstick cooking spray.
In a mixing bowl, beat together the cake mix and ingredients for making cake.
Using a large scoop, divide the batter between the cupcake liners.
Place one, unwrapped, frozen Cadbury Egg in the middle of each cupcake liner.
Bake cupcakes for 15 to 18 minutes or until a toothpick inserted to the sides of the egg comes out clean. (Do not pierce through the center where the egg is.)
Allow cupcakes to cool for 5 minutes in the pan before transferring to a wire rack to cool completely.
Place the frosting in three different piping bags.
Snip the tip from the piping bags and place all three piping bags in a larger piping bag fitted with an open star piping tip.
Pipe frosting from the middle of each cupcake to the outer edge and back to the middle to create a peak.
Press one mini Cadbury Creme Egg into the peak of each cupcake.
Decorate with sprinkles if desired.