First, preheat the oven to 170 °C. Fill the baking tray with about 1 cm of water and put it in the oven. Brush the ramekins with butter and sprinkle with sugar; refrigerate. For the soufflés, first scrape out the pulp from the vanilla pod. Mix the pulp with the egg yolks and half the sugar using the bamix® whisk. Then, roughly chop the chocolate in the bamix® processor and transfer to a bowl. Heat a pot full of water and place the bowl with the chocolate on top to melt. Then, stir the coffee and the melted chocolate into the egg yolk mixture. Using the bamix® beater, beat the egg whites with a pinch of salt and the remaining sugar until foamy, then stir into the egg yolk mixture. Pour this into buttered and sugared ramekins. Bake in the preheated oven at 170 °C for about 25 minutes, then serve immediately.