Ingredients

  • 6 ounces high quality semisweet chocolate, cut into small chunks
  • 1/4 cup dark rum
  • 4 eggs, separated
  • 3/4 cup sugar
  • 1/4 cup strong brewed coffee
  • 8 tablespoons softened butter, cut into chunks
  • 1/4 teaspoon cream of tartar
  • 1 pinch salt
  • 1/2 cup heavy cream

Method

  • Combine chocolate and rum in a small pot; nestle pot inside a larger pot filled with water and set aside to allow to melt.
  • Beat yolks in another small pot until pale and frothy.
  • Combine sugar and coffee in another pot; cook over medium heat until dissolved, 5-6 minutes. Pour coffee mixture into yolks in a stream, while whisking, set aside.
  • Pour water into a large pot to a depth of 2". Heat over medium-low heat until hot but not simmering. Nestle pot with yolk mixture over pot and cook, whisking vigorouslym until thick and creamy, about 8-9 minutes. Transfer yolk mixture to a clean bowl; beat with an electric mixer until cool; about 5 minutes.
  • Uncover chocolate mixture and stir; add butter and whisk until smooth. Fold chocolate-butter mixture into yolk mixture; set aside.
  • Beat egg whites in a bowl until just frothy. Add cream of tartar and salt; beat to stiff peaks. Stir 1/4 of the egg whites into chocolate-yolk mixture; gently fold in the rest. Spoon mousse into 6 serving cups or dishes. Chill until set. Beat cream to stiff peaks; transfer to a pastry bag with a star tip. Pipe a rosette of cream onto each mousse.