4 sq. unsweetened chocolate
2 egg yolks
4 c. confectioners sugar, sifted
2 tsp. melted butter
6 tbsp. thin cream
1 tsp. vanilla

Melt chocolate and butter over water. Beat egg yolks, mixing with some sugar until stiff. Mix both adding cream and the remainder of sugar alternately. Beat until creamy, then spread on cooled cake.