To prepare a key lime coconut cupcakes white chocolate frosting recipe, first you need to prepare the cupcake batter. First, you'll need 2 cups of white sugar, 1 cup of butter, and 2 tablespoons of vanilla extract. Then, add the dry ingredients to the wet ingredients and mix until combined. Next, pour the batter into cupcake liners and bake for 18 to 20 minutes or until toothpick inserted in the center comes out clean.