Melt the chocolate in a double boiler and set aside. Beat the yolks with the 2 tablespoons of sugar with an electric mixer at high speed until light and fluffy. Stream in the melted chocolate at low speed.
Dissolve the gelatin in the warmed liquor and stream slowly, along with the coffee, into the chocolate mixture at low speed. Transfer the mixture into a stainless steel bowl and refrigerate until needed.
In another mixing bowl, whip the egg whites and the remaining 1/4 cup sugar to a stiff meringue with an electric mixer. In a separate bowl whip the heavy cream until firm. Fold the meringue into the chocolate mixture, then fold in the whipped cream. Refrigerate for at least 1 hour before serving.
Consumption of raw or undercooked eggs, shellfish and meat may increase the risk of foodborne illness.