Pre-heat your oven to 350F - 180C and line 2 baking sheets with baking paper.
Combine the butter with sugar in a bowl and mix until creamy and light.
Stir in the egg yolks (for fine crumbs, grate them through a fine grater) and mix until well combined.
Add the hazelnut meal and stir in the flour, baking powder and salt and mix until sandy.
Add 1-2 tablespoons of warm water, just until the dough comes together.
Slightly knead the dough then place it on a floured working surface.
Cut the dough into smaller pieces then roll each piece into one thin stick with 6-8mm diameter.
Cut the long stick into 8-10cm sticks then take each piece of dough and cut in half lengthwise, but only ¾ way through. You will get two thinner parts of dough. Take each part and roll it backwards to form 2 small rolls.
Watch the pictures below to better understand the procedure.
If you want, you can add raisins or pices of turkish delight in the center of each roll, like in the picture below.
Place the cookies on your baking sheets and cook for 15-17 minutes until slightly golden brown.
Remove the cookies from the oven and while still hot, roll them through powdered sugar.