We tried this 2 yrs ago with a 22 lb turkey. We cooked it on our Weber grill at around 375 and used the cookie sheet. It was a big hit and very juicy. My sis-in-law did it the next year and added fresh herbs w/ olive oil under the skin. It turned out perfect and the oven was free for all the other side dishes.

My open-concept house is now full of greasy smoke. 450 degrees????...This is a turkey not a pizza! I reduced the temp. and legnthened the time so I can breath. Perhaps I missed something. I am glad that I tried this on a non-holiday day! Oh my! Clean up will take several days.

I usually always to a large 20lb or bigger bird this way, very successfully. It takes about 2-2.5 hours; use a thermometer as Martha suggests for your first time. I have tried it on a flat wire rack and it gets done faster, but I like the flavors that it absorbs when you lay it over herbs and veggies. Then I puree those vegies to thicken my gravy. I'll be honest....I do not like white meat at all...but I'll eat this it's so moist!

I agree with SJRL, cook two 12 pound turkeys, just as easy an the white meat won't dry out so much as with a huge bird. And not so blasted heavy when lifting each bird separately. I thought about brining my turkey this year, but could not get one smaller than 14 pounds, so will be spatchcocking it instead, it is just so much easier to me.

I don't know that I would ever do a 21 pound turkey - I'd rather do 2 10-12 pound turkeys. A 21 pounder is likely to dry out regardless of method before it cooks through.

Can this be done with a 21 lb turkey? How long would it take in the oven?