Loaded Tuna Casserole

I saw this on Pinterest the other day and it looked good and satisfying.  So, I altered it a little and made it for my family.  It turned out great!  It's loaded with lots of good stuff, like mushrooms and onions, and topped with crunchy French fried onions.  Yum!  It goes great with some salad on the side.  Enjoy!
-3 Tbs extra virgin olive oil
-1 onion, finely diced
-8 oz baby bella mushrooms, chopped
-8 oz small pasta (rotini, shells, etc)
-1 (10.5 oz) can cream of mushroom soup
-1 cup sour cream
-3/4 cup milk
-1 tsp garlic powder
-1/2 tsp salt
-1/2 tsp pepper
-4 cans (5 oz each) tuna in water, drained
-1 1/2 cups shredded Monterey Jack cheese
-1 package (3 oz) French fried onions
Preheat the oven to 375 F.
Heat olive oil in large skillet.  Add the onions and mushrooms and cook until veggies are nice and tender, for about 5 minutes.
Bring a small pot of water to a boil.  Add the pasta and cook for only about 8 minutes.  Drain.
While the pasta is cooking, to the onion mixture, add the mushroom soup, sour cream, milk, garlic powder, salt and pepper.  Mix well and cook for a couple of minutes.
Add the drained pasta and tuna.  Mix well.  Pour into 9x13 baking dish.  Sprinkle on top with the cheese and the French onion.
Bake in preheated oven for 10 minutes. Enjoy!
Adapted from a recipe found here.