Wash and clean the rhubarb and cut into small pieces. Mix flour and baking powder. Separate eggs. Whisk yolks.
Stir in 100 g sugar, vanillin sugar, fat and milk. Stir in flour mixture, rub in marzipan and fold in rhubarb. Line the hollows of a muffin tray (12 hollows) with a paper baking tin each. 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. Remove the muffin tray. Let muffins rest for about 5 minutes. Beat the egg whites with the whisks of the hand mixer until stiff. Finally, pour in 120 g sugar.
Carefully remove the muffins from the baking tray and place them on a baking tray. Spray meringue tuffs onto the muffins and bake at the same temperature for about 4 minutes. Take them out and let them cool down. If necessary, put them into colourful paper baking cups