Line a springform pan (26 cm Ø; approx. 8 cm high) at the bottom with baking paper. Bring the cream and espresso to the boil, remove from the stove. Break 200 g chocolate into pieces, melt in it while stirring. Let it cool down. Cover and chill for about 3 hours.
Separate eggs. Beat the egg whites, 3 tbsp. cold water and 1 pinch of salt until stiff, adding sugar. Beat the egg yolks separately. Sift flour, starch, 2 tbsp. cocoa and baking powder on top and fold in. Brush into the form. Bake in the preheated oven (electric cooker: 175 °C/circulating air: 150 °C/gas: level 2) for 30-35 minutes. Let cool down
Cut through the floor 3 times horizontally. Whip the chocolate cream for about 1 minute until creamy. 1⁄3 Spread the cream on the 1st cake base. Place 2nd cake base on top and spread with 1⁄3 cream. Place the cake base on top and spread with the remaining cream. Press the last cake layer lightly on top.
Coarsely chop the couverture and melt it in a hot bain-marie with plate-fat. Cover the cake with it. Break 50 g chocolate into small pieces and melt. Pour into 1 freezer bag and cut off a small corner at the bottom. Decorate the cake with it. Chill for about 1 hour. Dust the cake with cocoa to create a Christmas motif