Years ago, my mom found this in one of Emilee Barnes' books. It is so easy to have a moist turkey with this slow cook method! My husband hated white meat until I used this method. If you wish your turkey skin to brown, do not cover the turkey. I usually cover it because I think I get more broth when covered. In fact, I usually get so much broth that I need to get some broth out with my baster mid-way through the roasting time so that it doesn't spill out over into the oven.
Preheat the oven to 350 degrees.
Remove the gibblets. (They will be inside the cavity somewhere in a white bag.)
Wash turkey well, dry turkey with paper towels. Salt the cavity.
Rub outside of turkey with olive oil.
Stick meat thermometer into the turkey. (I skip this.)
Place breast down on a rack in your large roaster. (I don't have a rack, and it works fine.)
Roast one hour at 350 degrees to destroy surface bacteria.
Adjust heat to 180 to 200 degrees for a turkey of any size. Roast one hour per pound.
Once the turkey is done, it will not overcook. You can leave it in the oven for an additional 3 to 6 hours and it will not overcook.
Just a tip: if you have a newer oven, if may have a safety mechanism that will turn off the oven automatically after twelve hours. Since for me, this is usually in the middle of the night, before I go to bed, I turn off my oven, then quickly turn it on again. Then I don't have any surprises in the morning!
I usually get a very large turkey (over 20 pounds) because I like to have lots of leftovers. I was told that turkeys over 20 pound have a greater to meat to bone ratio. I'll chop up the cooked meat, put it in pints and use it for any recipe calling for cooked chopped chicken. A great time saver! But this size turkey can be a real pain to thaw! I can barely fit it into my fridge! I found a simpler way, that I think is rather safe. I place the turkey in a large ice chest, and fill with cold water. The turkey will thaw faster if the water is changed often. I sit in on the counter next to my large laundry sink. It is rather easy to pull the plug on the ice chest, drain out the water, and then refill several times until it is completely thawed.
Note: A reader just told me that she uses an large electric roaster for her turkey. No cluttering up your oven for those long hours!