Chocolate Brownie Icing

1 square {1 oz} unsweetened chocolate
1 tbsp soft butter
1 cup sifted icing sugar
1/4 tsp vanilla
2 tbsp milk

Melt chocolate over hot water {in top of double boiler}.  Cream butter, vanilla & half icing sugar until fluffy.  Add melted chocolate.  Add remaining sugar & milk arlternately.  Beat until smooth.