Place 1 paper baking tray in each of the recesses of a muffin tray (for 12 pieces) (or: place 3 paper baking trays in each other)
Cream butter, sugar, vanillin sugar and salt. Stir in the eggs one by one. Mix flour, baking soda and baking powder and stir in alternately with the buttermilk in portions
Fill half the sponge mixture into the muffin tray. Spread a good half of the marshmallows on top. Spread the remaining dough on top. Bake in the preheated oven (electric cooker: 200 °C/circulating air: 175 °C/gas: level 3) for about 25 minutes
Roughly chop the chocolate (approx. 1/2 cm large). Cut the remaining marshmallows in half each. Mix with the chocolate, spread on the muffins about 5 minutes before the end of the baking time and bake
Leave the muffins to cool in the muffin tray for about 5 minutes. Then remove them from the trays and let them cool completely. Dust with icing sugar shortly before serving