Tuna Noodle Casserole

I was searching for a Tuna Noodle Casserole that didn't require Cream of Mushroom Soup or peas.  I finally modified a couple of different recipes I had seen online, and this is what I came up. 

3 cups uncooked egg noodles
3/4 cup chopped celery
1/3 cup chopped onion
1/2 cup chopped red bell pepper
1 tablespoon vegetable oil
1 (10.75 ounce) can condensed cream of broccoli soup, undiluted
1 cup shredded Cheddar cheese (plus extra to sprinkle on the top)
1 cup milk
1 (12 ounce) can tuna, drained and flaked
2 Tbsp mayonnaise
salt
black pepper

1. Cook noodles according to package directions. Meanwhile, in a skillet, saute the celery, onion and red pepper in oil until tender; set aside. In a saucepan, combine the soup, cheese and milk. Cook and stir over low heat until cheese is melted.
2. Drain noodles; place in a large bowl. Add the celery mixture, soup mixture, tuna, mayonnaise, and salt and black pepper to taste. Pour into a greased 8-in. square baking dish. Sprinkle extra cheese on top.  Bake, uncovered, at 350 degrees F for 25-30 minutes or until heated through.