Step 1 as for Basic Sweet Soufflé.
Beat egg yolks with sugar and vanilla essence and mix well with batter. Stir in Grand Marnier.
Pre-heat oven to 350°F. (Mark 3). Line a buttered soufflé dish with halved sponge fingers sprinkled with cognac. Beat the egg whites until stiff, but not dry, and fold into the cooled batter mixture. Pour into prepared soufflé dish. Bake 35 minutes or until soufflé is puffed and golden. Serve with apricot or rich vanilla sauce.