Mix flour and baking powder. Whisk the egg. Stir in sugar, salt, vanilla sugar, butter and buttermilk. Carefully fold in the flour mixture. Line the hollows of a muffin tray (12 hollows) with paper cups and spread the dough in them
Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 25 minutes. Let muffins rest for about 5 minutes. Carefully remove from the tray. Let them cool down
For the topping, briefly roast the pistachios in a pan without fat, remove. Wash lime hot, grate dry, grate peel thinly. Halve the fruit, squeeze juice from one half and cut the remaining half into 12 small slices. Chop the pistachios. Mascarpone, icing sugar, pistachio seeds, up to 5-6 teaspoons for sprinkling, mix lime peel and juice. Pour cream into a piping bag with a perforated spout and squirt onto the muffins as large tuffs. Sprinkle with remaining pistachios and decorate with lime wedges
Waiting time approx. 1 hour