Season the goulash (do not add salt to the Kasseler!) And fry everything vigorously in hot fat. Then add the onion and bell pepper and fry with it. Then deglaze with the stock. Stir in the ketchup and stew everything together - depending on the size of the pieces of meat - for 60 minutes. Add the drained corn and sour cream about 5 minutes before the end of the cooking time. Serve hot.