Sugar topping can add shimmer, crunch and color to your cookies for any theme. Sanding or crystal sugar is the best sugar topping to use on sugar cookies because it will not melt into the cookie at room temperature or with moisture from touching other cookies. Sanding and crystal sugar can be purchased colored or you can color it yourself to fit any theme. Decorating cookies with sugar topping is much like decorating with glitter, with icing being like the glue and sugar being like the glitter. It can be as detailed or as simple as you want the finished design to be.
Bake sugar cookies according to your recipe and allow the cookies to cool to room temperature. The cooler the cookies are, the easier it will be to ice and decorate the cookies.
Pour the sanding or crystal sugar onto the plate in a pile at least 1/2 inch thick and slightly larger than the diameter of the cookies.
Add the confectioners' sugar, milk and corn syrup to the bowl and stir with the spoon until the mixture is a smooth, creamy mixture with no lumps.
Dip the paintbrush in the icing and draw the design that you want on the cookie using the paintbrush. Quickly turn the cookie upside down and dip it in the pile of sugar topping. Place it sugar side up on a cool surface to dry for at least 10 minutes.