2 sq. unsweetened chocolate
1/2 c. butter (1 stick)
1 egg
1 tsp. vanilla extract
1 tsp. lemon juice
1 3/4 c. confectioners sugar

In 1-quart saucepan over low heat, heat chocolate and butter until melted and smooth. Remove from heat. Let stand 15 minutes to cool chocolate mixture slightly.

In small bowl, with mixer at medium speed, beat egg until mixed; beat in chocolate mixture. Add vanilla extract and lemon juice until smooth. Reduce speed to medium-low and gradually beat in confectioners sugar until mixture thickens and is smooth.