Knead the starch, flour, cocoa, icing sugar, vanillin sugar, espresso and fat into pieces. Form dough into 2 rolls (each approx. 15 cm long), cover and chill for approx. 1 hour
Line 2 trays with baking paper. Cut rolls into approx. 25 slices each. Cover 1 nut with each slice and shape into a ball. Place on the trays. Bake in a hot oven (electric cooker: 200 °C/ convection oven: 175 °C/gas: level 3) for 12 - 15 minutes. Cool down
Chop the couverture and melt in a hot water bath. Place the glaze in the bag in hot water for about 10 minutes. Mix the glaze lightly with the couverture. Dip biscuits halfway and decorate with chocolate-mocha beans. Let balls dry