Preheat oven to 425 degrees F.
Bring a large pot of lightly salted water to a boil. Cook pasta in boiling water for 8-10 minutes, or until al dente; drain.
In a large bowl, thoroughly mix noodles, onion, celery, 2 cups of cheddar cheese, tuna, soup, sour cream, milk, mushrooms and spices. Transfer to 9 x 13" baking dish.
Topping: melt butter and add to bread crumbs, cheeses and paprika. Mix until combined.
Spread topping evenly over casserole.
Bake for 20 to 25 minutes or until cheese is bubbly.