I use this on my Carrot Cake.

1 lb. powdered sugar
1/4 lb. (1/2 c.) soft butter
1/8 tsp. salt
1 tsp. vanilla extract
4 tbsp. milk
1/4 tsp. instant coffee

Cream 1/2 sugar and with butter and salt in large bowl. Blend extract, 2 tablespoons of milk and remaining sugar into mixture. Mix 1/4 teaspoon instant coffee in 1 tablespoon hot water. Gradually stir in remaining milk and add coffee to desired taste. Yields frosting for two 9 inch round layers.

Note: To make a more generous frosting, increase ingredients by 1/4.