To make the cake, start by dividing the egg yolks from the whites. In a large bowl, using an electric mixer with the whisk attachment, beat the eggs yolk while adding 1/2 cup of sugar. Beat until light and fluffy.
In another large bowl, add the remaining sugar and beat the egg whites on high speed until soft peaks form and it becomes fluffy.
With a rubber spatula, gently combine the beaten egg yolk mixture into the egg whites.
In a medium bowl, combine the flour, the baking powder, and the vanilla extract, adding it to the eggs by sifting it directly into the bowl, gently folding as you go.
Place a piece of parchment paper on a the pan. We used this high side sheet cake pan that is 17.7 by 13 inches. Spread the cake mix batter and level it with a spatula until it's in an even layer. Bake in a preheated 350° F oven for 6-7 minutes.
When it is ready, place the warm cake on a flat surface. Sprinkle the top of the cake with some granulated sugar. Finally, seal it with plastic wrap to keep it moist.
To make the filling, chop the chocolate into smaller pieces. Pour the cream into a saucepan and heat it being careful not to reach its boiling point. Once the heavy cream is warm, turn off the heat and place chocolate pieces into the warm cream.
Whisk both ingredients until they are combined and transfer the mixture to a bowl. Take a bowl of ice and place the bowl with your melted chocolate cream mix on top. Now start whipping with an electric mixer for 10-15 minutes until it is well-whipped. (It is ready when the color becomes similar to milk chocolate and the consistency is firmer).
Once the cake cools, gently remove the plastic wrap. Place about half of the whipped chocolate glaze on top of the cake and spread it evenly using an offset spatula, leaving about inch around the edges of pan.
Starting at the short end, roll cake up gently with the help of plastic wrap. Place the roll seam side down to harden in the fridge for about 1 hour. Put the leftover ganache in the fridge with the cake roll.
To decorate, use a large serrated knife to gently cut off a piece of your log, about 3 inches in length. Make the cut with a slight diagonal.
Use some of the chocolate ganache to attach the small log to the rolled cake. See photo for more details.
Spread the remaining chocolate ganache all over the cake. (With the help of a fork, make some lines to recreate the wooden texture all over the cake).
Use your creativity and imagination to create more branches and decorate with some berries and nuts.
Refrigerate until completely chilled before serving.