Mix cake according to manufacturer’s instructions. 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 350°F until cake springs back lightly when touched. Let cool completely. 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 pastry bag using different size and style star tips; also make a white buttercream bag. Smooth ice with white 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 quarter moon on the top of the cake at the edge and fill in with different sizes and colors of rosettes.
White Cake, Buttercreme, Buttercream, Orange, Pink, Violet, purple, Brown, Non-Pareils, Sprinkles, Layer Cake