I recently purchased a pre made casserole and the instructions stated that it should be placed in a 440* oven for 55 minutes. This seems like a very hot cooking temperature to me - am I mistaken? Thanks.
Assuming the packaging means 440°F, no, that's not that insane. Casseroles are heavy, with a lot of liquid, so it takes a lot of heat to heat them up, especially if this is a frozen premade casserole. It is on the high side, so you might want to make sure it's not browning too much on the top (cover with foil to shield if necessary) or burning on the bottom. You can always reduce the heat partway through if you have to; it'll just take longer.
If it's a thin item like a shallow casserole, it could make sense especially if the ingredients are already cooked. Also, is it a convection oven?
I also suspect this is a typo of 350. Especially given that the casserole is frozen, there's a high likelihood of the outside burning while the inside is still cool at 450. At 350, it will all cook and warm nicely.
Broil Temps are up to 550F. If you have a Self Cleaning oven, the temps can go to 850F for that function. Any temp that exceeds 600F must have an automatic door lock to prevent you from opening the door and being burned.
Hop that helps.