1. Position a rack in center of oven and preheat to 350 degrees F. Lightly coat a 10 x 15-inch jelly roll pan with vegetable spray or solid shortening. Line pan with baking parchment, and then spray or grease parchment. Dust parchment with flour and tap out excess flour.
2. Sift together flour, cornstarch, 1/3 cup of the cocoa, cinnamon, salt, baking powder, and baking soda. Set aside.
3. In large bowl of an electric mixer, whip 4 egg whites until foamy (reserve yolks). Gradually add 1/2 cup of the sugar while whipping to peaks that are stiff but not dry. Scrape whites into another bowl, set them aside (don't worry, they won't deflate), and return unwashed bowl and beater to mixer.
4. In same bowl, whip yolks, vanilla, and remaining < cup sugar together until thick and very pale in color (3 to 5 minutes or more, depending upon type of mixer used). By hand with a rubber spatula, fold about one-third of whipped whites into yolks to lighten them. Sprinkle on and gently fold in about one-quarter of flour-cocoa mixture; fold gently to maintain batter volume.
5. Alternately fold in remaining dry mixture and whipped whites until batter is fairly even in color; don't worry if there are a few streaks of white.
6. Scoop batter onto prepared pan and spread into an even layer. Bake 12 to 15 minutes or just until top is springy to the touch and a cake tester in center comes out clean. Don't over bake or cake will dry out too much to roll without cracking. While cake bakes, set a dish towel flat on counter and sift on remaining 1/3 cup cocoa, making a rectangle about 10 by 15 inches. (Note: After use, shake out towel over sink and wash in cold water - cocoa won't stain towel.)
7. As soon as cake is baked, invert it over sifted cocoa on towel. Lift off pan and peel off parchment. With a serrated knife, slice off a scant 1/8-inch strip around all crisp cake edges so that it will roll easily. Fold one short end of the towel over a short end of the cake, and roll them together. Set aside, seam down, on wire rack until cake is cold, about 1 hour.
8. Make the filling. Start by toasting the hazelnuts. Spread hazelnuts on a baking sheet and toast in 325 degrees F oven until fragrant and beginning to brown, 8 to 10 minutes. Let cool.
9. In large bowl of an electric mixer set on medium-high, blend cream cheese and confectioners' sugar until completely smooth. Add liqueur and vanilla and blend. Taste and adjust sugar or liqueur if needed. Finely chop nuts and stir in.
10. When cake is completely cold, unroll it and spread evenly with hazelnut cream filling. Re-roll cake and place seam side down on a plate. Dust surface with confectioners' sugar, or prepare a Buche de Noel.
11. For the Buche de Noel, make the Mocha Whipped Cream. Sift together cocoa and confectioners' sugar. In a medium bowl, combine cream and dissolved coffee (mix coffee granules in hot water). Use an electric mixer to whip cream. As soft peaks begin to appear, gradually add sugar cocoa mixture. Whip until peaks become a little firmer, but be careful not to over beat - about 3 minutes. Gently spread mocha whipped cream over prepared roulade.
12. To create a bark-like texture for a Yule log, run fork tines in cream along length of log. Keep refrigerated until ready to serve. May be prepared a day in advance and refrigerated. Just before serving, sift on a faint dusting of cocoa. If you wish, decorate the platter with sprigs of holly or pine.
Source: Hannaford fresh Magazine, November - December 2006