Buttercream Icing with variation: Black Icing
Tnn.foods.recipes/LMW (1999)

Best way to make black icing is to make CHOCOLATE icing first, then stir in Black Paste Coloring (Wilton sells it in Walmart, Michaels, etc). Only mix it until it gets a dark charcoal gray. It will darken in about 2 hours. to get brown, just make chocolate. You can make chocolate by just mixing in Hershey's Unsweetened cocoa.

I teach cake decorating. You can use a simple "buttercream" icing for your cookies. Just mix 1 cup shortening, 2 TBSP. water, and a little vanilla (about 1 tsp.) Then, add slowly, 4 cups sifted confectioners sugar. From there, add a little paste color to a color 2 shaded lighter than desired color. Thin icing as needed with either water or white karo syrup.