Melt the chocolate with the coffee in the top of a double boiler.
When the chocolate is completely melted, remove the pan from the heat. Beat the egg yolks until pale yellow and stir into the chocolate. Gradually stir in the Tia Maria. Cool the mixture. In a separate bowl, beat the egg whites gradually adding the sugar, until the whites are stiff. Whip the cream. Gently fold the whipped cream into the cooled chocolate mixture and then fold in the whites.
CAKE: Beat ingredients together at medium speed of electric mixer until batter is smooth. Grease a 11x15" jelly roll pan. Line it with waxed paper. Grease and flour the paper, shaking off any excess flour. Spread the batter evenly in the jelly roll pan. Bake for 10-12 minutes or until the cake tests done. Turn the cake on a rack and peel off the paper. Lightly oil a charlotte mold and line with the cooled cake. Cut the rounds of cake to fit both the top and the bottom of the moldm, and a strip for the sides. Place the smaller round in the bottom of the mold. Wrap the strip around the inside of the mold. You will probably have to piece one section of the side to cover completely. Don't worry the patches will be covered by the chocolate glaze. Spoon the chilled filling into the mold. Fit the larger round on the top of the filling. Chill for 3-4 hours or until firm.
CHOCOLATE GLAZE:- Melt the chocolate in the water and stir until smooth. Spread over the top and sides of the mousse cake and down the sides. Chill again. Serve in slender slices, it indecent ly opulent.