Chopping chocolate. Melt 150 g chocolate over a warm water bath. Coarsely chop the pecans. Cream butter, salt, vanillin sugar and sugar with the whisk of the hand mixer.
Stir in the eggs one by one. Mix flour, cocoa and baking soda. Stir in several portions. Stir in melted chocolate. Fold in 150 g chopped chocolate and nuts. Place 6 large blobs of dough (1 heaped tbsp. each) at a large distance on a baking tray lined with baking paper (cookies run apart during baking), press lightly with the back of the spoon.
Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for 12-15 minutes. Remove from the oven, place carefully (because still a little soft and fragile when warm) on a rack and let it cool down.
Bake 18 more cookies in the same way.