Reduce a baking sheet with aluminum foil to a size of 20 cm x 25 cm and line it with baking paper. Preheat the oven to 170 ° C.
The whole milk couverture is finely chopped and melted in a double boiler or in the microwave over low heat. Separate the eggs and beat the egg white with a pinch of salt to make snow.
Beat the butter, sugar and egg yolks until frothy and stir in the melted chocolate. Fold in the egg whites, almonds and flour with 1 tablespoon espresso powder. The dough is evenly distributed on the tray and baked on the middle rack for about 20 minutes.
As soon as the pastry has cooled down, cut into 3 - 4 cm cubes. Finely chop the dark chocolate couverture and let it melt. Mix with the rest of the espresso powder. Dip the surface of the cubes in the couverture and let them set.