CAKE: Preheat oven 390°F. Butter and line roll pan (not forgetting the inner rims!), then butter the liner. You don't want this cake to stick. Prepare a board with parchment paper for when cake comes out of the oven. Whip 4 egg yolks with sugar and vanilla until pale and creamy. Sift in flour a little at a time mixing each time until incorporated. Beat the egg whites to form soft peaks, then fold into the batter. Spread in roll pan and bake 9 minutes. Don't overbake or it will be dry. Remove from oven and immediately turn over onto your board. Remove pan and gently remove paper leave paper. Replace with new paper and also cover with a napkin. Roll papers, napkin, and all into log form. Let cool. FROSTING: Simmer (do not boil!) sugar and water until a thick syrup forms (stop when you see big bubbles.) If you go too far, add a little water and try again. Pour syrup into a clean mixing bowl. Whisk at the ready, add egg yolks, and whisk until mixture is cold. (The hot syrup will cook the eggs.) Mix-in softened butter. A cream will form. Split into two batches (or keep one batch and use 1/3c chocolate chips). Add melted chocolate to one, and the coffee extract to the other. Mix until smooth. ASSEMBLY: Unroll the cake. Remove napkin and top liner (carefully!). Mix rum and simple syrup. Use brush to cover entire surface. Spread coffee frosting onto the cake. Start folding up the shorter end of the cake, and roll as tightly as possible. Trim the ends, and remove one circle layer from each end. Place on top of the cake as cut branch decorations. Ice around with chocolate frosting. Sprinkle with confectioner’s sugar and fake or candy decorations (ivy leaves, berries, mushrooms.) Kids love to do this part! ;o)