Color some frosting with the Bright White gel paste and fill the bag with the 4 tip. Outline cookie with frosting and let set a good half hour. Take some frosting in a bowl, color white and add water, little by little, stirring until it's syrupy. Pour the runny frosting onto the middle of the cookie and spread to the edges with a small spatula or butter knife. Let set til firm a good two hours, even longer if possible.