For the turkey, with clean hands, insert your fingers between the skin and the meat at the neck opening and carefully break through the membranes between the skin and the meat all over the breast and thighs. Insert herbs neatly underneath the skin. Position the rack on the lowest level of the pressure oven. Set the pressure oven temperature to 450° F and the function to ROAST. Turn on the timer to preheat the oven. In a mixing bowl, toss together all of the cut-up vegetables and the garlic cloves. Spread them evenly in the pressure oven's baking tray. Tie the turkey's legs together at the ends of the drumsticks with kitchen string or butcher's twine. Fold the wing tips under. Season the turkey all over inside and out with salt and pepper. Drizzle and rub with some olive oil all over the skin. Place the turkey in the roasting pan on top of the bed of vegetables. Place the pan in the preheated pressure oven. Lower the pressure bar and set the timer to 55 minutes.* When the time is up, slowly release the pressure valve and slowly lift the pressure bar until no steam remains. Test the turkey for doneness: an instant-read thermometer inserted into the thickest part of the thigh not touching bone should read 165° F. If not, roast under pressure for 5 to 10 minutes longer. Remove the turkey from the pan to a platter and cover it with aluminum foil to rest for 15 minutes before carving. Skim any fat from the surface of the pan juices; reserve the juices in the roasting pan. Transfer the turkey to a carving board. Cut into serving pieces and serve with the roasted vegetables and garlic. * If cooking in a conventional oven, cook for 2 hours and 45 minutes at 350 degrees F or until the internal temperature reaches 165 degrees F.
