Preheat oven to 375 degrees F. Grease a 15x10x1-inch lipped cookie sheet or baking pan. Line pan with waxed paper. Generously grease waxed paper. Set aside.
Stir flour, cornstarch, and cocoa powder in a medium bowl. Stir baking soda, salt, and optional instant coffee into flour mixture. In a large bowl beat eggs, egg yolks, and vanilla with an electric mixer on high speed for 4 to 5 minutes or until thick and lemon-color. Gradually beat in granulated sugar, beating on high speed about 2 minutes more or until sugar is almost dissolved. Sprinkle flour mixture, one-third at a time, over egg mixture; using a large rubber spatula, gently fold in flour mixture just until combined. Evenly spread the batter in the prepared baking pan. Bake about 12 minutes or until cake springs back when lightly touched.
Remove the cake from the oven. Cool cake in pan on a wire rack for 3 minutes. Loosen the edges of cake with a small knife or thin spatula and turn cake out onto a clean towel generously sprinkled with powdered sugar. Carefully remove the waxed paper; discard.
While cake is warm, roll up the cake and the towel into a spiral, starting from a short side* of the cake. (It is important to roll the cake while it is still warm to avoid cracking.) Cool on a wire rack. Unroll cake; remove towel. With a thin metal spatula, spread the white Cream Cheese Frosting and Filling on the cake to within 1 inch of the edges.
Carefully roll up cake (without the towel) starting from a short side. Place, seam side down, on serving platter; chill for 30 minutes. With a serrated knife, diagonally cut off a 3-inch slice from one end of the cake. Place the diagonally cut edge of piece against the side of longer roll on the serving plate. This forms a "branch" on the "log.
Frost the entire cake with the chocolate Cream Cheese Frosting and Filling, carefully "cementing" the limb to the trunk with frosting. If necessary, chill until frosting firms. With the tines of a table fork, create a pattern of "rings" on the cut ends of the roll, and "bark" on the rest of the log. If desired, garnish log with Sugared Cranberries and rosemary sprigs. Sprinkle lightly with powdered sugar to give it that "just snowed on" look. Chill until ready to serve.
for the frosting and filling
In a large bowl beat cream cheese; butter; and vanilla with an electric mixer on medium speed until soft and fluffy.
Gradually beat in powdered sugar.
Place half of the mixture in a separate bowl; if desired, beat in almond extract. Set aside.
Beat unsweetened cocoa powder into the remaining cream cheese mixture.
Carefully monitor temperature of oven and time, while genoise (cake) is baking. It should be baked completely but just barely. The frosting does miracles in terms of covering of the sins of the genoise. Cracks can easily be repaired and then covered with the frosting.