Chop the leeks finely and braise them in part of the oil. Braise the chopped sauerkraut as well - close with a lid to smother.
Once the sauerkraut softens, prepared an oiled tray.
Stack the sheets in it, sprinkling them with oil and alternating between the sauerkraut and leek stuffings every 2 sheets.
Finish off the zelnik with 2 sheets, then cut it into large squares.
Pour on water and oil.
Bake it until reddened.