Chicken Vegetable Casserole

Recipe is from Aunt Nellie.

1 cup spaghetti, cooked and drained
¼ cup finely chopped onion
¼ cup chicken fat or butter
1/3 cup flour
1 tsp salt
Dash pepper
1 ½ cups chicken stock
1 cup milk
1 pkg frozen peas
2 cups cooked, diced chicken
½ cup grated cheese

Cook spaghetti in boiling salted water until tender. Drain and rinse in hot water. Sauté onions in chicken fat or butter for 5 minutes. Blend in flour, salt and pepper. Add chicken stock and milk. Cook, stirring constantly, until thickened. Add frozen peas, spaghetti, and chicken. Mix well. Pour into a 2-quart casserole. Sprinkle with cheese. Bake in 350 degree oven for 30 minutes. Serves 6-8.