For hamburgers, combine all ingredients thoroughly. Shape to form dozen thin patties. For filling, combine all ingredients throughly. Spread filling on center of 6 of the patties. Cover with remaining patties; pinch edges together to seal. Place in broiler about 10 cm from source of heat. Cook about 7 minutes. Turn and cook about 5 minutes longer. Serve on toasted hamburger buns. FAVORITE HAMBURGERS: Omit onoin salt in above hamburger recipe. Add quarter cup finely-chopped onion and 1- half teaspoons salt. Combine all ingredients thoroughly. Shape to form 6 patties. Broil or pan-fry about 7 minutes. Turn and cook 4 to 5 minutes longer.