Butter Cookies with Marbled Mint Icing

These shortbread cookies will awaken the artist in you, without requiring any particular skills. To create a marbled effect, simply prepare a royal icing with powdered sugar and egg whites, to which you'll add a few drops of food colouring, and then swirl using a toothpick. Simply dip the cookies into the minty icing, for a technique that's as refreshing as the cookie's flavour.