Cake
Preheat the oven at 250 degrees Celsius.
Pour the flour, potato flour, baking powder and the cacao powder in a bowl and mix it together .
Whip the sugar and the eggs for the cake really fluffy and white.
Continue whipping and add all the dry ingredients.
Place a baking paper on a baking sheet.
Pour evenly the batter on the paper.
Bake the cake in the middle of the oven during 5 minutes.
Take out the cake and let it cool down.
White chocolate mousse
Mix the whip cream to a hard foam.Take out the cake and let it cool down.
Melt slowly the chocolate on low heat in a casserole.
Mix the egg yellows in a bowl and add slowly the chocolate.
Add the whip cream very gently in the bowl and stir slowly.
Place the mousse in the fridge for minimum 2 hours.
Dark chocolate mousse
Mix the whip cream to a hard foam.
Melt slowly the chocolate on low heat in a casserole.
Mix the egg yellows in a bowl and add slowly the chocolate.
Add the whip cream very gently in the bowl and stir slowly.
Place the mousse in the fridge for minimum 2 hours.
Place evenly the white chocolate mousse on the cake bottom and roll it together gently.
Spread evenly the dark chocolate mousse all over the cake, and make nice long stripes with a fork.
Place the cake cold until serving.