Peel, wash and grate the potatoes. Warm 5 tablespoons of buttermilk slightly and dissolve 1 tablespoon of espresso powder in it. Mix flour, baking powder and baking soda. Whisk the egg. Stir in sugar, vanilla sugar, butter, espresso buttermilk and other buttermilk. Sift the flour mixture on top and fold in carefully. Finally fold in the grated potatoes
Line the troughs of a muffin tray (12 troughs) with one paper form each. Spread the dough in them and bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for approx. 25 minutes. Remove the muffins and let them rest for about 5 minutes. Carefully remove from the tray and let them cool down
Warm up the sour cream a little, dissolve 1 tbsp. espresso powder in it and let it cool down. Mix mascarpone, espresso sour cream and icing sugar and fill into a piping bag with star spout. Spray cream onto the muffins and decorate each with a mocha bean. Keep cold until serving
Waiting time approx. 45 minutes