Have the butcher cut the liver in thin slices. Wipe with a clean damp cloth and then roll in flour and brown in hot fat. Now add tomatoes, onions, and green peppers. Cover closely and cook for five minutes, then add cornstarch, salt, paprika, mustard, and cold water. Dissolve the starch and spices well and then bring the mixture to a boil and cook slowly for fifteen minutes. Now place mashed potatoes on a large platter, shaping them flat on top. Lay the slices of liver on and then pour over them the sauce and garnish with nicely brown strips of bacon. Sprinkle with finely chopped parsley and serve.