Mix the flour, water, sugar and salt with a wooden spoon until a sticky dough is formed. (now let it rest for at least 2-3 hours, preferably overnight)
Roll out the dough into a thin, square shape. Roll out the cold butter in a square between baking paper or foil, too, so large that it can be placed on the dough as a diagonal square and does not (!) Extend over the edges of the dough (to visualize: open envelope = dough size, folded letter = butter size) now put the butter on the dough and fold the dough back over to form an envelope
Unroll everything again in one direction, the result is a long square ...
Now fold the short sides of this square back to the middle, then fold the whole thing up again .. Let it rest for 20 minutes
Now roll out the dough again (this time the direction of rotation has been rotated by 90 °), fold it up again as described in step 3 ... let it rest for 20 minutes
Repeat step 5 twice
7 .... and roll out again. Now cut the dough into 12 rectangles and put a dollop of plum jam on each one. Roll it up carefully, pressing down the edges a little. Place on a baking sheet and brush with egg yolk. ... and let it rest for another 2 hours.
Preheat the oven to 210 °. Brush the rolls again and bake for 20 minutes.
Now the rolls are ready. If you like, add a little powdered sugar or a sugar glaze ... The recipe takes a little time, but the taste rewards the effort!
Filling variant: chocolate