Pour milk on bread dressing and allow to soak for 5 to 10 minutes. Mix hamburg, bread dressing mixture, cheese, onions and ham together. Season with salt and pepper. Form into meatballs of desired size. Brown meatballs either in frying pan or oven (350 for 35 minutes) Add drippings from which fat has been removed, to the mushroom soup(undiluted). Heat but do not boil. Add sour cream to mushroom soup a little at a time and stir thoroughly. DO NOT BOIL. When sauce is heated, pour over meatballs in casserole dish. Add sauteed mushrooms if desired. Return to oven(325) for 5 to 10 minutes.Serve over boiled rice. CAN BE MADE AHEAD AND FREEZES WELL.