Preheat the oven at 250 degrees Celsius.
We will start by preparing the cake bottom. Pour the dry ingredients in a bowl.
In another bowl whip the sugar and the eggs whites very fluffy and white. Continue whipping and at the same time add the dry ingredients mixture.
On a baking sheet, place a baking paper. Pour the batter on the paper.
Place in the middle of the oven for 5 minutes. Take out the cake bottom and let cool down.
Continue to prepare the white chocolate mousse by whip the whip cream to a hard foam.
Melt the chocolate on low heat in a casserole. Let it cool down a few minutes.
Whip the egg yellow and add it the melted chocolate.
While stirring very slowly add the melted chocolate in the whip cream.
Place in the fridge for minimum 1 hour.
Continue by preparing the dark chocolate mousse. Mix the whip cream to a hard foam.
Melt the chocolate on low heat in a casserole.
Whip the egg yellows and add it the melted chocolate.
While stirring very slowly add the melted chocolate in the whip cream.
Place in the fridge for minimum 1 hour.
Now it is time to prepare the cake. Cut the cake so you have two pieces for layers in the cake and a bid part that will cover the cake.
Place the part that will cover the cake in a bûche cake form. The cake will be upside down.
Add half of the dark chocolate mousse on the bottom. Place the middle layer of the cake bottom on top of the dark chocolate mousse.
Place the white chocolate mousse on top of the cake layer. Place the bottom layer on top of the white chocolate mousse.
On top of the bottom layer place the plate you will use to serv it on. Hold on tight and turn the cake upside down so the cake is standing on the serving plate.
Take away the bûche form and spread evenly the rest of the dark chocolate mousse all over the cake.
As decoration you can make it look like a log and even place some small Christmas decorations on top.