To make shell melt butter with 4 ounces chocolate in saucepan over low
heat. Remove from heat and add 2 cups sugar and eggs. Combine flour, baking
powder and salt and beat into chocolate mixture. Add vanilla. Line greased
15- x 10-inch jelly-roll pan with waxed paper. Pour in batter and spread
evenly. Bake at 350F 12 to 15 minutes, or until cake springs back when
lightly touched. Cake should be soft, not crisp. Turn out on rack and cool.
Meanwhile, to make filling, combine 12 ounces chocolate and 1/4 cup coffee
in top of double boiler and melt over hot water. Remove from heat. Beat egg
yolks until pale yellow and stir in some of chocolate mixture. Return to
chocolate in pan, stirring until smooth. Gradually stir in liqueur and
cool. Beat egg whites until foamy. Gradually add 3 tablespoons sugar and
beat until stiff. Whip cream until stiff. Fold cream into cooled chocolate
mixture, then fold in egg whites.
Invert brownie shell on towel and peel off paper. Line bottom and sides of
greased 9-inch square baking dish with brownie shell, cutting strips for
sides and 9-inch square for bottom. Turn filling into cake-lined dish and
cover with plastic wrap. Chill 3 to 4 hours or until firm.
To make glaze, combine 4 ounces chocolate and 3 tablespoons coffee in top
of double boiler and melt over hot water.
Invert chilled dessert onto serving platter. Coat with chocolate glaze. Let
glaze set and decorate with chocolate curls. Cut into very thin slices to
serve.
