Position rack in lower third of oen and preheat to 350 degrees. Butter a 10 1/2 by 15 1/2 by 1 inch jellyroll pan and line the bottom with baking parchment. Lightly butter the parchment. Place the yolks in the small bowl of an electric mixer fitted with beaters or the whip attachment. Beat on medium speed until they are thickened and light yellow in color, about 2 minutes. Add 2/3 c sugar, 1 Tbsp at a time, taking about 2 to 3 minutes to blend it in well. Reduce mixer speed to medium-low. Blend in the vanilla, orange rind, and orange juice, and mix for 15 seconds. Reduce speed to low, add the cocoa, and blend until just incorporated. Remove from the mixer and transfer to a larger mixing bowl. Set aside. Wash and dry beaters. In the large bowl of the mixer, whip the egg whites and water at medium speed until frothy. Add the cream of tartar, increase the speed to medium-high, and continue beating until the whites form soft peaks. Add 1/4 c sugar, 1 Tbsp at a time, taking about 30 seconds. Whip for 15 seconds longer. Do not overbeat. Remove the bowl from the mixer. With a 2 3/4 inch wide rubber spatula, fold one quarter of the beaten egg whites into the yolk mixture, taking about 20 turns to lighten. Then fold in the remaining whites, taking an additional 30 to 40 turns. Pour batter into the prepared pan and gently smooth the top with the back of a spoon, spreading it evenly into the corners. Tap the pan gently on the counter to even out the batter. Bake in the preheated oben for 20 to 25 minutes, until the top feels set and is springy to the touch. While the cake is baking, prepare a 20-inch piece of baking parchment. Place on a flat work space and sprinkle lightly with 1/2 tsp granulated sugar. Remove cake from the oven and immediately invert onto the parchment. Protecting your hands with potholders, remove the pan and gently peel off the paper pan liner. Tightly roll together the cake and the sugared parchment paper away from you, starting on a long side. Place the cake seam side down on a cake rack to cool while you prepare the filling. To make the whipped apricot souffle: Put the apricots and 1 cup of water in a small heavy saucepan, cover, and bring to a boil. Simmer 20-25 minutes or until the apricots are very soft and all but 1 or 2 Tbsp of the water has been absorbed. Remove from the heat and add 1/2 c confectioners sugar. Whip with a fork until the apricots are very smooth. You should have approximately 1/2 c of puree. Put 1 Tbsp cold water in a small heat-proof glass dish and sprinkle the gelatin over the top. Let stand for 5 minutes without stirring. Place the dish in a skillet filled with 1/2 inch of boiling water. Stir the mixture until the gelatin is dissolved and the mixture is clear. Stir it into the apricot puree. Set aside to cool to tepid. Beat the cream in a small chilled bowl of an electric mixer. As it begins to thicken, add 1/4 c confectioner's sugar gradually. Beat until soft peaks form. Remove from the mixer and fold in the tepid puree and the Grand Marnier by hand. To assemble: Carefully unroll the cake, but not completely flat; the edge closest to you should remain curled. Spoon the filling under the curled edge first, then spread it over the rest of the cake evenly with a metal spatula, leaving a 1-inch border on the far side. To roll the cake, tuck the curled edge under and continue rolling. Place seam side down on a wooden breadboard or oblong platter. Cover loosely with foil and refrigerate until hald-hour before serving. Dust the top with confectioner's sugar just before serving. Store leftover roulade in the refrigerator loosely covered with foil for up to three days.