Purple, sky blue, lemon yellow, orange, and pink food coloring
Step 1
Preheat the oven to 350°F. Grease and flour two 9-inch round cake pans. Prepare the cake mix according to package directions and divide the batter evenly between the pans. Bake until golden and a toothpick inserted in the center comes out clean; about 28 to 31 minutes. Transfer to a wire rack and cool for 10 minutes. Invert the pans and cool the cake layers completely.
Step 2
Tint one can of the vanilla frosting a pale blue. Spoon 1 cup of vanilla frosting into a resealable bag. Tint 1/2 cup of the remaining vanilla frosting violet and spoon it into a resealable bag. Divide the remaining frosting into four small bowls and tint these orange, pink, yellow, and bright blue. Spoon each of these into a resealable bag.
Step 3
Trim the tops of cakes to make them level. Place one cake layer on a serving platter and spread 1/2 cup of the light-blue frosting on top. Arrange the second cake layer on top. Cover the entire cake with a smooth layer of the remaining light-blue frosting. Refrigerate the cake for 30 minutes to firm it.
Step 4
Print the Sprinkles cake template. Cut out Sprinkles and place the template lightly on top of the chilled cake. Mark Sprinkles outline with a toothpick. Remove the template.
Step 5
Snip a 1/4-inch corner from vanilla-frosting bag, pipe the outline of Sprinkles, and then fill in the outline. Carefully spread the frosting to make it smooth.
Step 6
Mark Sprinkle's spots and other features with a toothpick, using the tmeplate as a reference. Snip small corners from remaining frosting bags and pipe the outlines and details with the colored frosting. Pipe dots around the cake with any of the remaining frosting.
