Stuffed Hamburgers
["1 lb. ground meat", "1/2 c. canned milk", "1 c. bread crumbs", "1 tsp. salt", "1/8 tsp. pepper", "onion slices", "4 tsp. mustard"]
["Combine.", "Shape into 8 flat patties.", "Spread 4 patties with about 1 teaspoon mustard.", "Cover with remaining patties.", "Pinch together with wet hands."]
["ground meat", "milk", "bread crumbs", "salt", "pepper", "onion", "mustard"]