• Make 24 white cupcakes according to the instructions on the package. Allow them to cool completely.
• While the cupcakes are cooling, prepare the frosting (see recipe below).
• Cut the cupcakes into thirds horizontally. 
• Put a dollop of blue frosting on the bottom layer of the cupcake. Add the middle cupcake layer and put on a dollop of red frosting. Finally, add the cupcake top and a dollop of white frosting.

Fluffy Buttercream Frosting

• Beat butter, shortening, and vanilla until creamy.
• Add powdered sugar, one cup at a time, beating at low speed until well blended.
• Add heavy cream and marshmallow cream, beat until light and fluffy.
• Divide the frosting into three parts. Tint one bowl of frosting blue, one of the red. and leave the third one white.