For the marinade, finely chop the onion. Put diced game in a sealed container, add the onion, bay leaf, cloves, thyme, rosemary, mix well and pour over the red wine and vinegar. Marinate 2-3 days in the refrigerator. Drain marinade (save it), put the meat in a clay pot. Passaged diced onion in melted butter, sprinkle with a little flour and fry, add the meat, pour 150 milliliters of the marinade, add the green pepper, tomato paste. Close the pot and put into a cold oven. Cook at 225 degrees Celsius about 70 minutes. Slice the mushrooms and with sour cream add to the pot, add salt, add sugar and cook for 20 minutes.