Chop the onion. Finely chop the garlic. Put the meat in a non-oxidizing dish, add bay leaf, pepper, cloves, chop onion, chopped garlic, pour kvass, keep for 1 hour in the cold.
Melt the butter. Remove the meat from the marinade, dry, rub with salt and fry on a baking sheet in the oven until cooked, pouring oil and juice that stands out.
Cut the prepared meat into pieces, put in a deep frying pan, pour kvass in which the meat was marinated, bring to a boil and remove from heat.
Serve with baked potatoes. Serve horseradish and pickles separately.