It is an old and almost forgotten Russian dish. It needs special preparation – kroshevo (medley) – from gray leaves of cabbage. You know, those coarse green cabbage leaves (the first or second layer) that most people leave in the store shelf.
These leaves are very finely chopped, crushed with salt and fermented for a few days. Some recipes ask for 2-3 days for zaparivanie – brewed with boiling water. For rapid fermentation rye flour or sweet carrots were added. Such leaves were fermented in oak barrels, but today I used just a glass jar.
For shchi fermented cabbage was slowly cooked with meat and broth or just with water in the preheated cooling Russian oven, I suggest using slow-cooker.