Watercolor Cake

This stunning watercolor effect is a surprisingly simple cake decorating technique that makes the dessert incredibly special.
Prepare the cake layers according to the recipe or instructions on the package.Prepare the frosting: Beat together the butter, vanilla extract, and salt in an electric mixer on medium speed until creamy, about 1 minute. Gradually add the powdered sugar, beating until fluffy, about 3-4 minutes. Add the milk, 1 tablespoon at a time, until the frosting has a smooth, spreading consistency.Spread the icing between the layers, as well as on the top and sides of the cake, to make a layer of crumbs.Divide the remaining frosting into 5 small bowls. Using 1 color per bowl, add 1-2 drops of paint to each bowl. (We used yellow, pink, purple, orange, and blue.)Apply several pieces of icing of each color randomly on the sides and top of the cake. Use an offset spatula to smooth out the icing around the cake. (*Don't use too many brushstrokes, otherwise the colors will look muddy.)If desired, mix the 2 icing colors in a pastry bag and circle the edges of the cake with a pattern.