Put some of the chopped onion, carrot, and celery mixed with thyme on the bottom of the roasting pan and add 1 cup of water
Put the rest of the chopped onion, carrot, thyme, and a bit of melted butter inside the turkey
Put a v-rack in the roast pan. Baste the turkey all over with some melted butter and start the turkey breast side down.
Cook the turkey for 45 minutes.
Use paper towels to hold the hot turkey and turn it on its SIDE. Baste with melted butter and cook another 20 minutes.
Turn the turkey onto its other side, baste and cook another 20 minutes.
Finally, turn the turkey breast side UP, baste, and cook another 45 minutes or so, until a meat thermometer in the leg registers 170-175F and one in the breast 160-165.