L in large sauce pan set to medium hi heat combine soup and sour cream amd mix well

Start adding the cheees (no more than half) to taste should be rich and creamy. (you should cook the macaroni wile waiting for the cheese to melt)

After sauce is nice and creamy add 3 cans of tuna and mix well. (try not to beat it up to much if you like it lumpy)

Drain macaroni well. pour sauce mix into your macaroni pan and put macaroni back in with sauce mix and mix well.

Pour your macaroni mixture into a 13x9 baking dish and spread out evenly.

Start topping with the rest of the cheese. (or to your liking) and then top with frenches onoins.

Place casserole into pre heated 350°F degree oven and cook until cheese is melted and onions are golden brown