Use a knife to separate the red, white, and blue parts of the popsicles. Place each color in a separate bowl and microwave until the popsicle has melted. Separately measure out ⅓ cup of each popsicle color.
Divide the cake mix into thirds. Each third should be a little more than 1 cup. Place each cup of cake mix into a separate bowl.
Spray the cake pans with non-stick spray. Preheat the oven to 325˚F.
In the first bowl, add in 1 egg white, ⅓ cup of the red melted popsicle, and 2 tablespoons of vegetable oil. Whisk until the ingredients are combined. Add in a few drops of the red food coloring and mix. Divide the batter between 2 of the cake pans.
In the second bowl, add in 1 egg white, ⅓ cup of the white melted popsicle, and 2 tablespoons of vegetable oil. Whisk until combined then divide the batter between 2 of the remaining cake pans.
In the third bowl, add in 1 egg white, ⅓ cup of the blue melted popsicle, and 2 tablespoons of vegetable oil. Mix until combined. Divide the batter between the last 2 cake pans.
Place the cake pans into the oven to bake for 25-230 minutes or until a toothpick inserted comes out clean.
Remove the cakes from the cake pans and allow them to cool completely on a wire rack.
Use a star shaped cookie cutter to cut out a star from the center of the red and white cakes.
Transfer the frosting into a piping bag fitted with a circle tip.
Pipe the frosting onto the top of one of the red cake layers, going around the star cut-out. Fill the star cut-out with pop rocks.
Place one of the white cake layers on top of the red layer. Pipe the frosting on top, going around the star cut-out. Fill the star cut-out with pop rocks.
Place one of the blue cake layers on top of the white layer. Proceed to frost the top and sides of the cake and repeat steps 10-12 to assemble the second cake with the remaining cakes.