What is the cooking time for a stuffed turkey at 350 degrees? I read that it should be 20 minutes per pound, is this correct?
Stick a thermometer in the stuffing; when the stuffing is at 160F, you're done. Since heat radiates inwards from the outside, you don't want the very middle of the dish (where the stuffing is) to be any colder than needed to kill salmonella. Estimate a bit longer than an unstuffed turkey.
Turkey is done when the internal temperature reaches 160° F. That's the temperature required to kill the bad stuff; so any cooking for any longer just dries out your turkey unnecessarily.
However, getting to this temperature varies depending on a lot of factors like your oven, the turkey's construction, and the exact phase of the moon. (Just kidding about the moon - kinda.)
The generally accepted formula for estimating cook time at a standard 350° F bake is 20 minutes per pound of turkey + another 20 minutes. Thus, an 11 pound turkey would reach 160° F in about 4 hours. (Note that this is for a truly fully defrosted turkey.)
If you're doing a traditional "shoved into the raw turkey cavity" thing, add another 20 - 30 minutes to get the stuffing up to the 160° F. temperature. Since the stuffing is put into the raw cavity, it's likely to absorb raw turkey juices, which must be brought up to the same safe temperature.