For the Husarenkrapferl, mix butter with sugar, yolks, lemon zest and cinnamon until smooth and finally mix briefly with the flour. Let the dough rest in the refrigerator for about 2 hours.
Roll the dough into finger-thick strands, cut off 1 cm pieces and form them into balls, roll them in the hazelnuts.
Place them on the baking tray lined with baking paper and press a hollow with your little finger. Fill the hollow with jam using a piping bag (or cut off a small piece of jam from a frozen bag).
Bake 2 trays at 160 °C convection oven for approx. 15 minutes until light.