For an old-fashioned brown sugar icing, heat butter, milk and brown sugar to a boil, remove from heat, stir-in powdered sugar and vanilla, and beat until creamy. For an old-fashioned confectioner's sugar icing, stir together confectioner's sugar, milk and vanilla extract.
For the brown sugar icing, constantly stir 1/3 cup of butter, 1/4 cup of milk and 1 cup of brown sugar over low heat in a 2 quart saucepan. Let the mixture boil for two minutes, and allow the pot to cool before stirring in two cups of powdered sugar one cup at a time. After adding in 1 1/2 teaspoons of vanilla and beating the mixture, stir in about 1/2 tablespoon of milk if the mixture is too thick to spread. This recipe makes enough icing to cover a 9-by-13 loaf cake. The mixture can also be used to make candy by adding chopped pecans and placing on a buttered plate to chop up.
If the confectioner's sugar icing is too thick, add more milk, and if the icing is too thin, add more confectioner's sugar. To color the icing for decorating cookies, separate the icing into a few bowls and add food coloring for the desired color. Place icing in the refrigerator for up to three days, but bring up to room temperature before using to ice cookies.