Preheat oven to 375F/190C.

Cream together the butter, sugar and egg yolk until well combined.

Add the hazelnut and regular flour, mix well and bring the mixture together into a ball.

Roll out mixture on a lightly floured surface to about ¼in/3-4mm thick and cut with cutters or into shapes.

Place cut shapes onto a baking sheet/tray and bake for approx 8-10min until lightly brown. If they go a bit browner they will still taste fine, they will just be a bit more brittle.

Decorate as desired (simple icing is confectioners/icing sugar mixed with water on an approx 4:1 ratio).