Mix 2 pounds, 7 ounces of water and Dawn Exceptional Bakers Request White Cake Mix on low speed for three minutes. Cream 3 minutes on third speed of a 4-speed machine (2nd speed of 3-speed machine); Incorporate oil and remaining water for one minute on 1st speed. Scrape down. Blend three minutes on 1st speed.
Measure out 3 pounds batter, deposit 1 pound 8 ounces into a sprayed and papered 8-inch cake pan. Repeat again to make 2 cakes total. Bake at 350F until cake springs back lightly when touched. Let cool completely.
Once cooled, trim the bellies of each cake, saving them for other uses. Place one cake round on a cake board, and fill with buttercream. Place the other round on top and crumb coat with buttercream.
Place buttercream in 3 bowls, color one orange, using a drop or two of brown to mute the color. Repeat with the pink and purple, also muting slightly with brown. Place each colored buttercream in a different size and style star tip, also making a white buttercream bag. Smooth ice with buttercream. Pipe a very small amount of each color around the sides and top of the cake and smooth ice again to swirl the colors. Trace a waning moon on the top of the cake and fill in with different sizes and colors of rosettes. Top with white sprinkles just on the rosettes.