Sift flour onto bench, cut butter into small cubes and add to the flour. Add sugar, make a well in the centre and add yolks and then almonds. Bring together with your hands and work into a smooth dough for a few minutes. Roll into a ball and cover with cling-wrap. Rest in the fridge for an hour.

Preheat oven to 175C.

Break off small pieces of the dough, about 60g each, and roll into 10cm-long pieces with the ends slightly tapered. Bend into crescent shapes. Place on a tray lined with baking paper and bake for about 15 minutes. They should be very lightly golden but not brown.

Remove from the oven, allow to cool a little. Roll in the vanilla sugar while still hot (when they are cool, the sugar will not stick properly).