This sporty megaphone cake is made from a standard-size cake that's cut into a few simple shapes. It's sure to score megapoints with everyone at your cheerleading party.
Spread a sheet of parchment paper over the cardboard, securing it in back with clear tape.
Cut the cake and arrange it on the board as shown. Tint the frosting with the yellow food coloring, then frost the cake yellow.
Next, cut a large doughnut in half and frost it yellow. Place the doughnut handle at the bottom of the megaphone, about 2 inches from the narrow end, and secure it with frosting.
Use a toothpick to draw the outline of the number (about 4 1/2 inches tall and 3 inches across) onto the plastic backing of the fruit leather, then cut out the number shape. Cut 2 fruit leather stripes about 3/4 inch wide and place them on the cake along with the number.
With blue decorators' icing, outline the number and the edges of the cake. Squeeze icing onto the handle and spread it to cover the top of the handle. Pipe a birthday message onto the parchment paper. Secure M&M's to the board with tiny dabs of icing so they appear to be bursting out of the megaphone along with the happy-birthday cheer.