Preheatthe oven to 160 degrees Celsius or 320 degrees Fahrenheit on circulating air.
For the base, melt the butter in a pot on medium heat. While stirring continuously for about 10 minutes, let it become brown. Then remove from heat, carefully add 1 tbsp. cold water (Attention: it may splash!) and let it cool down.
Mix the cooled butter with the sugar, salt, espresso powder, baking powder and egg, then slowly add the flour and cocoa powder. Place the batter into a greased cake ring and spread it flat. Pre-bake in the oven for 10 minutes.
For the cheesecake filling, stir the cream cheese until creamy, then add in one at the time: the icing sugar, vanilla sugar, eggs, a pinch of salt and starch, stirring continuously. Finally fold in the whipped cream and the chocolate chunks.
Using a spatula, pour the cheesecake mixture from the mixing bowl onto the pre-baked base and smooth it down. Wrap the wet cake strip of fabric or kitchen paper around the tin (so that the cake rises evenly, see description above) and bake in the oven for 50 minutes.
After the baking time, switch off the oven and let the cake cool down for at least 30 minutes in the closed oven. Decorate with fruits and nuts as desired.