Stir the coffee and milk together and add it in 2 lots to the egg mixture, while alternating between it and the dry ingredients.
Divide the mixture up into 2 identical 8″ (20 cm) diameter forms, laid out with baking paper and lightly greased, and bake in a preheated 356°F (180 °C) oven for 30-35 min. until dry on the inside. While you're waiting for the layers to cool, make the cream.
Melt the crumbled chocolate in a water bath and add warm water or the cream, stir and finally add the butter. Leave the homogenized mixture to cool at room temperature and harden a bit. Once the cream cools, beat it with a mixer.
Cut each layer into 2 separate ones - for a total of 4. Stick them in pairs with your favorite jam and put cream between the 2 pairs. Smear the entire cake generously with cream on top. Leave the cake to cool for a few hours before serving.