Place sauerkraut in a large saucepan or casserole dish and cover with about 1 litre of boiling water. Add prunes, bay leaves and allspice. Simmer for 50 minutes until tender.
Meanwhile, pour boiling water over the mushrooms and let soak to rehydrate, then drain and chop, reserving the liquid.
Heat the oil in a frying pan. Add the onion and sausage then cook while stirring until the onion is soft and sausage is browned.
In a separate saucepan bring about 1 litre of water to the boil. Add beef, pork and bacon. Simmer for 20 minutes, then drain.
When sauerkraut is soft, add the drained meat mixture, sausage, onions and mushrooms then mix well. Simmer uncovered for 20 minutes over low heat.
Pour in red wine and cook for a further 15 minutes. Season with caraway, marjoram, salt and pepper. Stir in tomato puree, if using. If the stew is dry, pour in water reserved from mushrooms and simmer for a few minutes to let the flavours combine.
Enjoy straightaway, or for richer flavour continue to slow cook the stew, covered, over low heat, stirring occasionally. Bigos is becomes tastier the longer you cook it.