Serves: 8 to 10 This mousse-filled, chocolate-swathed mold is an embarrassment of riches. When served to chocolate lovers, the only sound in the room will be faint moans of pure, unadulterated decadent pleasure. Filling: Melt chocolate with coffee on top of a double boiler. When chocolate is completely melted, remove pan from heat. Beat egg yolks until pale yellow and stir into chocolate. Gradually stir in Tia Maria. Cool mixture. In a seperate bowl, beat egg whites, gradually adding sugar until whites are stiff. Whip cream. Gently fold whipped cream into cooled chocolate mixture and then fold in egg whites. Preheat oven to 350. Beat ingredients together at medium speed of electric mixer until batter is smooth. Grease an 11-by-15 inch jellyroll pan. Line it with waxed paper. Grease and lightly flower paper, shaking off any excess flower. Spread batter evenly in jellyroll pan. Bake for 10 to 12 minutes or until cake tests done. Turn cake onto a rack and peel off paper. Lightly oil a 2-quart charlotte mold and line with cooled cake. Cut rounds of cake to fit both top and bottom of mold, and a strip for sides. Place smaller round in bottom of mold. (you will probably have to piece one section of side to cover completely, but don't worry; any patchwork will be hidden by chocolate glaze.) Fit larger round of cake on top of mold. Chill for 3 or 4 hours or until firm. Unmold and cover with glaze. Melt chocolate in water and stir until smooth. Spread over top of mousse-cake and drizzle down sides. Chill again. Serve in slender slices ~its indecently opulent. Hints: Melt chocolate in microwave. Its much faster. Instructions are on the chocolate package. A souffle dish makes a good replacement for the Charlotte mold.