03To decorate, melt the chocolate chips in the microwave in a heatproof bowl for 1 minutes. The chips may look unmelted, but stir them with a spoon to see if they have actually softened before putting them in for another minute, if necessary. Spoon the melted chocolate into a zipper-lock bag. Seal the bag, pressing out any air. Use a toothpick to make a very tiny hole in one corner of the bag to release a very thin stream of chocolate for writing.04To make the spiderwebs, spread white royal icing smoothly over the surface. Immediately, before the icing can set, pipe a spiral of chocolate over the surface, starting in the middle and working outward. Starting in the center, use a toothpick to pull outward through the icing, making a spiderweb design.05With beaters or a standing mixer, whip the egg white and lemon juice until frothy. At medium speed, beat in the confectioners' sugar, a little at a time, until the mixture is thick but still liquid enough to beat. Then beat on high until the mixture is thick and glossy, about 3 minutes. Cover the surface with plastic wrap while waiting to use it. Royal icing will set to a firm, glossy finish when applied to a cookie. The icing can be stored, tightly covered, in the refrigerator for up to a week.