Sometimes referred to as Sale Burgers in southern pa because they were common at church bizarres, public sales and the like. The burgers I know of were half cooked in a frying pan or flat-top then stacked in crock pots or steamer trays. Sauce was ketchup thinned down 1:2 with water and seasoned with a little each of mustard, Worcestershire sauce, minced onion, vinegar, salt, pepper, and sugar. Then they stewed for a while in the liquid.