I always hated the thought of tuna casserole. Especially the boxed/packaged ones, so I decided to make my own.
It's a good source of protein and calcium for the kiddies too!

Preheat oven to 350. You'll need a family size box of mac n cheese. On the stovetop, boil the macaroni noodles until tender and drain.
Add one cup of milk, and about two tablespoons of butter. Stir well. Add one can of cream of celery soup, one package of tuna, the cheese packet from the mac n cheese, mix well.
I add some finely chopped onion, but you could substitute frozen/canned peas or use both. I add black pepper to taste. Poor into a casserole dish, top with bread crumbs (instead of butter, I spritz the top with nonfat butter spray). Bake until heated through. About 30 minutes.