Buttercup Yellow Icing Color Wilton This gel-based Buttercup Yellow icing color gives you deep, rich color that won't change the consistency of your sweet treat. Perfect for coloring buttercream frosting, fondant, royal icing and more, this yellow gel food coloring is highly concentrated, so a little goes a long way. Get a cool, dark yellow buttercream for an Easter cake or a saturated, deep yellow for a striking birthday or wedding treat. Simply apply a small amount of food dye to your frosting or fondant using a toothpick, then mix to incorporate. Add more to deepen and darken the color. Also safe to use in batters, doughs and other foods, this edible yellow food dye is a great way to customize and personalize your treats.