Some decorations can be applied while pieces lay flat. Especially if you are attaching a heavy balcony or real candy, letting the frosting set up will save you some grief.
To make frosting you need 2 egg whites and 2 1/2 cups of powdered sugar. Beat egg whites until foamy, about 2 minutes on high speed. Add powdered sugar, 1/2 cup at a time, beating for at least 1 minute each time. Continue beating for at least 5 minutes after the last addition. This frosting can be kept, covered, for 1 day in the refrigerator.
Apply frosting with a decorator bag or spatula.
