Make candy buttons. Melt blue, pink and yellow Candy Melts candy. separately, according to package directions. Use melted blue candy in cut decorating bag to pipe about 1/4 teaspoon of candy into each cavity of candy melting plate; buttons will measure approx. 1/2 in. across. Refrigerate until firm, about 5 to 10 minutes. Make 32 blue buttons.
Repeat to make 32 pink buttons and 32 yellow buttons.
Make layered cake. Prepare batter following recipe directions. Bake and cool 2-layer cake. Prepare buttercream icing following recipe directions. Layer and fill for a 4 in. high cake. Use spatula and icing to ice cake smooth.
Use dots of icing to attach flat side of candy buttons to side of cake, making two vertical rows of four same-color candy buttons. Repeat four times around cake with each color.