Take the turkey out of the fridge, 1 hour before you are going to cook it to start bringing up it's temperature. A turkey that isn't fridge temperature will cook faster and more evenly.
Place the peeled and cubed root vegetables in a roasting pan or a large sheet pan if you don't have a roasting pan. Toss with cooking oil. Set aside.
Make sure you have a rack in the middle of your oven and the second one is just far enough below for your roasting pan or sheet pan with the root vegetables to fit.
Now heat the oven up to 425 degrees.
Once the oven is heated up, the turkey goes right on the middle rack. Make sure the legs are running perpendicular to the metal bars.
Place the root vegetables below the turkey and close the oven door.
Cook for 30 minutes, before dropping the temperature down to 350 degrees for the remainder of the cook time.
Cook until a thermometer reads 155 degrees when inserted into the thickest part of the breast. Carryover heat will continue to cook the bird until it reaches 165 degrees. On average it takes about 40-50 minutes for it to reach this temperature but don't go by time, check the temperature to be sure.
Remove the turkey from the oven and allow it 30 minutes to rest.
To finish the panzenlla, add in the Brussel sprouts, bread cubes, and garlic. Stir everything up and cook for 15 more minutes. Then pull from the oven, season with the thyme, salt, and pepper and the vinegar if you want to use it.
Carve the turkey up and serve with the panzanella.