Melt chocolate, dissolved coffee, and Curacao or rum in a medium bowl set in a barely simmering pan of water. Stir frequently to hasten melting. Or, melt in a microwave on medium (50%) for about 2:15. Stir until smooth. When mixture is warm and smooth, whisk in egg yolks and combine well. Remove from heat and set aside.
In a clean, dry mixing bowl, beat egg whites and cream of tartar on medium speed until soft peaks form. Gradually sprinkle in 2 tbsp sugar, beating on high speed until stiff but not dry. Fold one-fourth of the egg whites into chocolate mixture to lighten it. Scrape all of the remaining whites on top of mousse and set aside while you beat the cream. Beat cream until it holds its shape softly (do not beat until stiff).
Scrape whipped cream over egg whites and chocolate. Fold together until just incorporated. Turn the mousse immediately into lined mold or serving bowls.
From the Dinner Co-op