Melt butter in a saucepan, stir in cocoa and 1/8 l water.
Preheat the oven to 175 degrees.
Sift the flour and baking powder into a bowl, mix with sugar and 1/2 teaspoon salt, slice open the vanilla pod, scrape out the pulp and add (I have already reduced the amount of sugar and then used vanilla sugar).
Mix the cocoa butter, eggs and cream thoroughly with the flour. Pour the dough into the mold (I use a 26 cm springform pan, or a loaf pan for cakes) and bake in the oven for 45-50 minutes (chopsticks test!)
For the glaze, mix powdered sugar with 5 tablespoons of water, melt the butter, add cocoa and powdered sugar and stir everything thoroughly.