Gently rinse the elderflower umbels and, if necessary, pat dry with kitchen roll.
Beat yolks with sugar and vanilla sugar or scraped pulp of a vanilla bean until foamy.
Mix flour with a pinch of salt and with 1 tablespoon of finely grated and roasted pumpkin seeds and stir with rum into the yolk-sugar mixture.
Beat egg whites until stiff and fold in.
Fold in prepared elderflower umbels and bake in a pan with heated oil.
Make a mixture of powdered sugar, cinnamon and finely grated and roasted pumpkin seeds and sprinkle over the elderberry doughnuts.
Serve warm!