Mix sour cream, crème fraiche and mustard well. Squeeze the coleslaw and drain in a sieve. Wash and slice the radishes. Halve the onion and slice it as well. Wash the lettuce and drain. Heat the oil in a pan and fry the meat loaf on both sides. Cut the buns open and spread the mustard cream on the undersides. Top with onion, radish, coleslaw, liver loaf and some lettuce. Place the top half of the bread on top and press down a little.