Southern Macaroni & Cheese

I'm adding this macaroni and cheese recipe per Heather's request. Not too sure what the "Southern" part of this recipe is-it's just what my great grandmother called it, so we'll got with that.

1 box (8 oz) Macaroni, cooked and drained
1 small jar of chopped pimento
1/4 Cup chopped onions
2 cans cream of mushroom soup
1 cup mayonnaise
1 lb. grated cheddar cheese
cracker crumbs
Miz all the ingredients together except the cracker crumbs. Place in dish and top with cracker crumbs. Bake 350 degrees for 20-25 minutes.