1 c. (6 oz.) semi-sweet chocolate pieces
1/4 c. boiling water
2 tbsp. confectioners' sugar
4 egg yolks
1/2 c. butter
2 tbsp. rum (or vanilla, or Grand Marnier)

Place chocolate in a food processor and run the machine until the pieces are ground. Scrape down sides and with machine running add boiling water. Process until quite smooth. Add sugar, egg yolks, butter and rum and process until smooth. If too warm, chill to spreading consistency. Because of the egg yolks, refrigerate the cake after frosting. This does wonders for an ordinary cake!