Mocha Buttercream

Combine the sugar, water and cream of tartar in a heavy saucepan. Bring to a boil and boil rapidly until the syrup reaches 240°F. on a candy thermometer.

Beat the egg yolks until fluffy. Gradually beat in the syrup and continue to beat until the mixture is stiff.

Melt the chocolate in the coffee over hot water. Beat into the egg-yolk mix