Chicken Tetrazzini

6 large chicken breast
2 medium-sized onions
8 oz. spaghetti
1/2 lb. butter
1 scant cup flour
1 qt. part of broth and milk
1 can cream of mushroom soup
1/2 lb. American cheese
1/2 lb. old english cheese
cracker crumbs

Boil chicken and cut up into small pieces. Saute onions in butter.
Make cheese sauce of 1/2 lb. butter, one scant cup flour, and one quart part of broth and milk. Grate 1/2 lb. american and 1/2 lb. old english cheese. Make sauce in large pan. Add grated cheese and let blend. Add one can mushroom soup. Fold in chicken and spaghetti. Have bottom of two large square or oblong casseroles covered with crushed and buttered cracker crumbs. (I put only on top) Pour in chicken mixture. Cover top with buttered crumbs.
Bake 30 to 40 minutes until brown. Don't cook or brown until time to serve, as it needs to be served hot. If this is frozen, be sure to take out and thaw before time to cook and serve.