Over hot water in top of double boiler, beat the eggs and sugar until mixture is very light and almost white in color. Remove from heat. Meanwhile, melt the butter and skim off the foam. Return to heat and melt the chocolates. Beat the sifted cornstarch slowly into the egg mixture on low speed until thoroughly blended. Stir the vanilla and orange liquer into the chocolate mixture and then into the egg mixture. Spoon into a 10-inch springform pan that has been greased and floured.
Bake at 325 F for 20-25 minutes, until torte pulls away from sides of pan. Kinfe inserted in center will not come out clean. DO NOT OVERBAKE! Cool in springform pan. Remove ring.
To make the glaze, melt chocolate and butter with the cream and spoon over cooled torte. Refrigerate and chill completely.