The cold butter to combine with the sifted flour quickly grind to education crumbs.

Add to flour crumbs, three egg yolks and the sugar (I have brown, but again, ideally, there must be powdered sugar, I just ended it not during).

Quickly knead the dough, divide it into two equal parts. One of them add cocoa and sour cream. Mix the chocolate dough. It turns out two types of dough. Each wrap in plastic wrap and put into the refrigerator for 50 minutes.

After 50 minutes take the dough and divide each ball into 4 pieces, I chocolate even 5 divided, as I have more work.

Restitutive each part into a rectangle about 11*18 cm is Better to do it between sheets of parchment paper. I took a large sheet of paper, he laid out layer by layer. And each layer was rasschityval between two small sheets, and then the top is removed, turned over the sheet with the dough and put them on a common pile, then carefully removed the bottom sheet. Phew, don't know if it is clear to explain, but something like this. The main thing - to adjust. Each layer Wake walnuts.

Alternate layers of white and chocolate batter.

Continue until all the dough. Now we have to wrap everything in parchment paper and go on top with a rolling pin, slightly press the layers. Sent wrapped dough for 30 minutes in the freezer.

After 30 minutes take the dough and cut with a sharp knife with a thickness of about 1-1,5 cm. Spread cookies on the baking tray lined with parchment paper. Sent in preheated to 180 degrees C oven, for 20 minutes.

Give the liver to cool completely, preferably in the oven, and then you can put the kettle on and call everyone on the evening Cup of tea, help yourself!!!