Creamy Tuna and Shells Casserole

This was SOOOO good, I'm not a huge Tuna fan, and I've tried Tuna Casseroles before and never liked any of them. Also the mayonnaise kind of threw me off and I almost didn't add
it at the end because of how moist the recipe was, But I threw it in anyway and it was delicious in there!!! Everyone here loved it!

Creamy Tuna and Shells Casseroles Recipe #126573

Smooth creamy sauce--very yummy.
by Chef Aduladi
1 hour 30 min prep

SERVES 4 -6

1 (6 ounce) can tuna (drained)
1 (8 ounce) can cream of chicken soup
1 (8 ounce) can cream of mushroom soup
1 small onion
1 cup chopped celery
8 ounces mushrooms (sliced or chopped up)
1 cup mayonnaise (NOT Miracle Whip)
1 cup milk
1 (8 ounce) package large shell pasta
1/4 cup butter, for sauteing vegetables
2 cups shredded cheese, mix jack or cheddar cheese

Preheat oven to 350°F.

Cook shell pasta according to package directions.
Add butter to sauté pan on low-med heat.
Add celery and onions.
Sauté until onions almost clear.
Add mushrooms - remove from heat.
Drain veggies (if extra butter in pan).
Put veggies in pan, add soup, tuna, milk, cheese until heated through and cheese melted.
Remove from heat add mayo and cook pasta.
Pour into baking dish, top with remaining shredded cheese bake until cheese is melted and "browning" (approx 1/2 hour).
Remove and let sit for about 5 minutes.
Eat.