Chop chocolate in pieces.
Melt chocolate and butter over bain-marie.
Whisk eggs and sugar for about 3 minutes.
Mix in melted chocolate.
Sieve and mix in flour, cocoa powder, baking powder and coffee powder.
Scoop the dough with an ice scooper or a tablespoon and place on baking tray with baking paper.
Bake in preheated oven at 180° C for 8 minutes.
Leave to cool on baking tray.