Instructions:
Set aside 2 tablespoons of the allotted sugar, then whisk the remainder in with the egg yolks until thick and pale. Stir in the extract. Whisk the egg whites until soft peaks form. Whisk the rest of the sugar into the egg whites until it is stiff. Sift 1/2 of the allotted flour over the yolk mix, then add 1/4 of the egg white mix and mix together. Put in the rest of the flour and start folding it in with your hands or a plastic spatula. Then finally put in the rest of the whites and mix it in. Spread this mix out evenly on the jelly roll pan and bake for about 15 minutes.
Sprinkle some sugar onto a sheet of wax paper and flip the cake over onto it. Roll it up (so that it is shorter and thicker rather than longer and skinnier) with the wax paper in it, and let it cool. In the mean time you can make the filling.
Boil the cream and pour over the chocolate in a heat-proof bowl to let it melt. Beat this mixture with a mixer until it's thick. Take a third of the mix out and set it aside, then stir the rum into the larger portion. If it is really runny and too liquid, you might consider chilling it an hour or so until it's spreadable. When ready, unroll the cooled cake and spread the chocolate rum mix onto it evenly. Re-roll it--no wax paper in between layers this time--and now you're ready for ornamentation.
If you desire--though this isn't necessary--slice off a little piece of the end at a slant and then stick it to the side like an off-growing branch. Whether or not you do this, the next step is to frost using the set-aside cream-chocolate mix. Spread it all over the top and sides so that it is completely covered except for the ends that look like the inside of a cut-down tree. Drag a fork across the surface carefully so that it ends up resembling tree bark. When it's set, sprinkle some powdered sugar on top like snow. Put on a plate and if you like garnish it with cookies, candy coins, or seasonal decorations.