1 (6 oz.) pkg. chocolate morsels
1/4 c. butter
1/2 c. sour cream
2 1/2 to 2 3/4 c. sifted powdered sugar
1 tsp. vanilla
1/4 tsp. salt

In the top of a double boiler, melt the chocolate chips and butter. Remove from heat and add the sour cream, vanilla and salt; mix well. Add 2 1/2 cups of powdered sugar, adding more as needed to make a thick but spreadable consistency.