To save time and oven space, I'm thinking of cooking root vegetables in the roasting pan with the turkey. Do you recommend this, or will the vegetables turn out mushy?
I do think this is difficult to pull off. You're right to worry about mush. If a lot of drippings collect in the pan, the vegetables will be poached in fat as much as roasted. The other issue is timing. Obviously your vegetables won't cook as long as your turkey needs to.
That all being said, if you control the amount of fat in the pan, add the vegetables at the right time, and give them a little room to breath, you could get a good result. Hopefully someone else can give precise recommendations.
Thanks to Michael and Antonia! All will be taken into consideration.
Another reason not to do it is that the vegetables will create steam right there next to the bird, interfering with proper roasting. You need dry heat for the best results when roasting a turkey, or just about anything else.
Here's what I'd do. I'd heat a large sheet pan in the oven while the oven itself is coming up to temperature, well before putting in the bird. When the oven is near the temperature you've set, put the prepped vegetables on the hot sheet pan, without parchment. The vegetables will sizzle! They'll cook up fairly quickly - but don't cook them all the way. Roast the bird, and when you take it out, and while it's resting, finish the roasted vegetables. If space is an issue then, because you are keeping other dishes warm in the oven, you can put the sheet pan on the very bottom, on the oven floor. If the oven is on, they won't need much time there.
Hope this helps. ;o)
In our Koji Turkey Recipe, we roast a broken down bird (a breast and two legs) on rack set in a sheet pan with root vegetable underneath. Because the turkey is in pieces, it takes much less time to cook and you wind up with caramelized, delicious vegetables. We also keep the vegetables in the oven after we pull the turkey from the oven to let it rest, tossing them once to develop browning. You can check out the recipe here: http://www.cooksscience.com/recipes/9339-koji-turkey/