Melt in saucepan:

2 tbsp. butter

Cook until tender:

1/2 c. chopped onion

Stir in:

1 can cream of mushroom soup
1/2 c. milk
1/2 c. drained chopped canned tomatoes
2 c. cooked med. noodles
1 c. cooked peas
2 c. tuna, drained and flaked

Pour into 2 quart baking dish (12 x 8 x 2 inches). Bake at 400 degrees 20 minutes. Stir, then top with sliced cheese and croutons. Bake until cheese melts.