Butter Biscuits

Place the flour, ground hazelnuts, butter, powdered sugar, cocoa powder, egg, cinnamon and a pinch of salt in a bowl and knead into a smooth dough.

Shape the dough into a roll about 3 cm thick.

Brush the outside of the dough roll lightly with water and roll it all around in 100 g of sugar.

Wrap the roll tightly in cling film and chill for about 2 hours.

Preheat the oven: fan 160 °C (conventional 180 °C). Line a baking sheet with parchment paper.

Unwrap the chilled roll and cut into slices about 1 cm thick. Place the slices on the baking sheet with some space between them.

Bake the cookies for 12–15 minutes and then let them cool briefly on the sheet.

Place the egg yolks and the remaining sugar in a heatproof bowl and beat over a hot water bath until the mixture becomes noticeably thicker and creamy.

Set the bowl into a cold water bath and continue beating the mixture until it has cooled and holds its shape.

Put the egg-yolk cream on the underside of the cookies and sprinkle with chopped pistachios. Allow to dry briefly if desired.