Bring half of the cream to a boil. Remove from heat and add the chopped chocolate. Let it rest for 2 minutes and mix. Let it cool.
Crush the Oreos© finely and mix them carefully with the butter. Press this mixture firmly into the bottom of an 18 cm diameter springform lined with baking paper.
Whip the rest of the cream until soft peaks form. Mix with the melted chocolate and then fold in the egg whites, which you have whipped with the salt to stiff peaks. Pour into the baking pan, smooth the surface, and let it set in the fridge for at least 3 hours.
Melt the white chocolate and put it in a piping bag or a paper cone. Arrange the Mikado’s© on a serving plate lined with baking paper. Pipe chocolate lines over the Mikado’s© to ultimately form a Christmas tree. Finish with the pink pepper and let it set in the fridge for at least 2 hours.
Remove the cake from the mold and dust it with cocoa. Finish it with a few pine trees and some icing sugar and serve the rest separately.