A recipe for this ingredient can be found elsewhere in this packet. In a bowl, put the chocolate, butter, Grand Marnier, vanilla extract, and almond powder together and mix. Melt the ingredients over a double boiler. Remove the mixture from the heat as soon as it's melted and whip lightly. In another bowl, whip the egg yolks with 0.75 cup sugar until a white ribbon is formed, about 5-7 minutes. Blend this sugar/yolk mixture gently into the chocolate mixture with a spatula. In another bowl, whip the egg whites vigorously. Slowly add 0.75 cup of sugar, whipping the mixture until lightly firm. Fold the egg whites/sugar mixture into the chocolate mixture blending lightly as for a souffle. Butter and flour two molds 25 cm in diameter and 5 cm deep. Place a sheet of parchment on the bottom of each mold. Put half of the mixture in each of the molds and bake at 140ºC for 1 hour and 20 minutes. Unmold and cool the gateau on a rack. To serve, sprinkle with powdered sugar and serve with Creme Anglaise.