Souper Tuna Noodle Bake
["1/2 c. chopped onion", "2 Tbsp. margarine", "1 can cream of mushroom soup", "1/2 c. milk", "1/2 c. drained tomatoes", "2 c. cooked noodles", "1 c. cooked peas", "2 (7 oz.) cans tuna"]
["In pan, cook onion in butter until tender.", "Stir in remaining ingredients.", "Pour into 2-quart baking dish.", "Bake at 400\u00b0 for 20 minutes or until hot.", "Stir. Top with sliced cheese and croutons. Bake until cheese melts.", "Serves 6."]
["onion", "margarine", "cream of mushroom soup", "milk", "tomatoes", "noodles", "peas", "tuna"]