Box of Macaroni (I like elbow, but sometimes get the bow ties)
Mayo
Onion
Can of Tuna
can of peas(if you want them - if not that is totally up to you)
(some people like to put boiled eggs in it, but I dont, totally up to you if you want them in it)
So just boil the noodles, cool, and add mayo, chopped onion, and can of tuna, salt and pepper to season...use as little or as much ingredients as you wish :)
Put in fridge (I like to wait a few hours before I eat it and it always taste better the day after)