Finely grind the nuts in the universal chopper. Knead flour, 100 g sugar, vanillin sugar, salt, egg yolks, butter and nuts in a mixing bowl with the dough hooks of the hand mixer to a smooth dough.
Form into a ball. Wrap in foil and chill for about 1 hour.
Break small pieces from the dough and roll and shape them into croissants on the work surface. Place on 3 baking trays lined with baking paper. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: see
manufacturer) bake for about 10 minutes. Remove and let cool on a cake rack.
Wash the orange, rub dry and rub half of the peel. Mix the orange peel with 75 g sugar. Halve the orange, squeeze the juice. Mix 4 tablespoons orange juice with icing sugar. Coat cooled croissants with orange icing, roll in orange sugar and let dry.