Next, add your Ahsoka Tano design to the front of your cake with white buttercream. Since buttercream is off-white, you can add some white-white icing color to brighten up the buttercream color. Then, take your Ahsoka Tano design stencil and carefully press it to the middle of the front of your cake. Use a knife to spread white buttercream over the opening of the stencil, then carefully remove the stencil to reveal your Ahsoka design left on your cake.