No way would I "cook" mac and cheese in a roaster oven. It won't brown on top and very likely will stick on the bottom.
I would cook the pasta and make the sauce on the stove top and keep it warm in the roaster.
but remember the longer you keep it warm, the dryer it will get....so have some milk or cream to add to it.

No stove top will be available unfortunately.

Then I would make it ahead at home and keep[ it warm on a styrofoam cooler insulated with an inch of newspaper covered in a towel.
4 pounds, assuming that's 4 pounds of cooked pasta with sauce, will be about 2 quarts. You can use 8 1/2 by 11 dishes and separate with cookie sheets or cardboard covered in foil. Stack them in the cooler....they will keep hot for easily 3 to 4 hours.

I should have used the word baked, not cooked. Starting with 4 pounds uncooked pasta. Sorry way to much chemo brain going on. I have to make it ahead of time and bake it there. No range will be available. I need to be there at 9 am and supper is at 5:30. This is a creamy recipe not a southern style. Thanks though.

After fully making the mac and cheese the day before/ahead of time, I would turn the mac and cheese out into disposable aluminum pans and cover with foil (make sure these pans will fit in your roaster). Transport pans and roaster to event. Place rack on bottom of roaster (most roasters come with), stack covered pans in roaster and heat through.

This way, you avoid the possibility of burning the pasta on the bottom and avoid a ton of clean up. Mac and cheese is already in serving vessels and even they get tossed.

1. Not all M & C recipes require baking.

2. Roaster oven can be used without burning the bottom because roaster oven has heating elements on the sides.

3. M & C cooked and reheated may become somewhat oily and not creamy. You may want to look into the Modernist M & C recipe/method.

Good luck.

dcarch

Thanks everyone. I think I will do a trial to make sure my recipe will work.

I agree, the roasters do not have bottom elements, they heat from the sides. Instead of bottom sticking you get that ring around the inside walls, which is just as bad. I think Mimi has the best idea. Make it ahead of time, put it in a disposable container that will fit within the well of the roaster (aluminum turkey roasting pan/etc. might work). The roaster is actually an oven, and so can easily be used like one. If you have a cooler or someplace to stash the assembled mac and cheese until baking time, it'll keep nicely until time to cook. If you use a couple of smaller pans, it'll take less time to cook, one large pan, I'd give it at least 2 hours to reheat.

Annie

Hmm....the roasters at church heat from the bottom....beans will burn and stick if you are not careful. I think they are old G.E roasters.

The long and short of it is that it's an oven so if the recipe says 350° for an hour that's what I'd go with but would allow some extra time if needed and keep in mind you need to heat the oven which will add some time to it. I'm in agreement with using the pans on the rack. The purpose of the rack isn't to keep it from burning since, as already said, most roaster ovens heat from the sides (although I believe my mother's Kenmore heated from sides and bottom) and the advantage of the rack and pan is you'll get better air circulation. It'll be better yet if you have a convection version which will make things any shade of brown you want and yes even black! I do like my "Roast-Air" Nesco.