ready in 50 min.
Heat the oven to 200°C (180°C in a fan oven), 400°F, gas 6 and line one or two baking trays with grease-proof paper.
Mix the butter with the icing sugar and vanilla sugar, then beat in the egg. Add the flour, ground hazelnuts and a pinch each of baking powder and cinnamon, and mix together. Use two teaspoons to place portions of mixture on the baking tray and scatter over the flaked nuts. Bake in the oven for around 10 minutes until golden.
Remove from the tray using the paper, and leave to cool completely. Dust with icing sugar before serving.