Mix flour, baking powder, cocoa, sugar, vanilla sugar and 1 pinch of salt in a bowl. Add butter and eggs. Knead first with the dough hooks of the mixer, then with your hands quickly to a smooth dough.
Knead the pistachios. Cover the dough and chill for about 20 minutes.
Preheat oven (electric cooker: 175 °C/circulating air: 150 °C/gas: see manufacturer). Line baking tray with baking paper. Quarter the dough and form it into rolls (approx. 3 cm Ø). Place on the baking tray with some space between them.
Bake in a hot oven for about 15 minutes. Take out and let cool down.
Cut the rolls diagonally into approx. 4 mm thin slices. Place some of the slices on the tray. Bake at the same temperature for 8-10 minutes. Take them out, remove from the baking tray and let them cool down. Bake the remaining slices in the same way.
Coarsely chop the chocolate coating and melt in a hot water bath. Spread a thin layer of this on the cantuccini and sprinkle with a little sea salt. Leave to dry.