4 blocks (4 oz.) Hershey's baking chocolate
1/2 c. butter
2 2/3 c. confectioners sugar, sifted
1 egg, unbeaten
6 tbsp. water
2 tsp. vanilla
1/8 tsp. salt

Melt chocolate and butter together in top of double boiler over hot, not boiling, water. Stir in the sugar, egg, water, vanilla and salt. Place the double boiler top in a bowl of ice and water. Beat with an electric mixer about 5 minutes or until frosting is of spreading consistency. Fill and frost layer cake.