Shell the walnuts and season them in a pan with some oil and rosemary.
Mix the flour with water, sugar, oil, and all the other ingredients as if you were making pizza or bread. The dough will have to be quite elastic like that of pizza, even if a little more sticky for sugar and oil.
Let this mixture rise overnight.

The following day mix the whole mixture together again for about ten minutes and then divide into 4 blocks.
Give each round the round shape to place on a greased and floured baking sheet. Then make a cross mark on each piece.
Let it rise for at least a couple of hours.

Finally, brush your dough with egg yolk.
Cook at 175°C for 45 minutes.