Now color your fondant using gel coloring, a few oz of each color will be plenty for a dozen cupcakes. You will need a light yellow, a dark green, and some white. Make sure to keep stored in a ziplock when your not working with it, so it doesn't dry out. As soon as your done coloring the fondant cut out two small squares (about an inch) from the yellow to be your butter. Then darken the rest of the yellow to a corn color.