From my step-mom, Nancy - Tastes very good on yellow cake.
6 tbsp butter, softened
2 2/3 cups powdered sugar
1/2 cup cocoa
1/3 cup milk
1 tsp vanilla
Beat butter. Blend in sugar and cocoa (which have been sifted together after measuring). Blend in milk and vanilla. Blend for 4 minutes on high until fluffy. (In an emergency for soupiness, add more powdered sugar and a little cocoa as needed.)
1 pkg. (4 oz.) BAKER'S Unsweetened Chocolate 1 lb. powdered sugar
1/2 cup butter or margarine, softened
2 tsp. vanilla 1/3 cup milk
Microwave chocolate in large microwaveable bowl on high 1-1/2 min., stirring every 30 sec. Stir until chocolate is completely melted. Cool 5 min. Add sugar, butter and vanilla. Gradually add milk, beating constantly with mixer on low speed until blended.