In a food processor add the almond powder, flour, baking powder and the vanilla sugar.

Mix for a few seconds, add the egg yolks and mix again to combine.

Finally add the soft butter.

Remove the dough from the bowl and cover the dough with a plastic wrap.

Put the dough into the fridge for 30 minutes.

Preheat the oven to 180C degrees.

Flour a clean surface and roll out the dough into a long log.

Cut into long sticks of 15 centimetres length and 3 centimetres wide then join the two ends to form a ring.

Flour a cookie pan and place the rings on the top.

Brush the rings with egg yolk and sprinkle the pistachio powder on top.

Bake for 20 minutes, till the bottom turns golden; then turn off the oven and keep the rings for 10 more minutes in the oven.

Remove allow to cool for 30 minutes.