Place turkey in refrigerator for 3 to 4 days until completely thawed.
Remove turkey thermometer and plastic truss from legs. Allow the turkey to air-dry in refrigerator overnight.
Remove turkey from refrigerator, pat dry on all sides with paper towels, rub down with grapeseed oil, and season all over with lemon-pepper seasoning; let come to room temperature for about an hour.
Preheat oven to 425 degrees Fahrenheit.
Place chopped vegetables on the bottom of the roasting pan along with chicken stock.
With turkey right-side up (turkey breast-side facing up), place in roasting pan and use foil to wrap wing tips.
Place turkey in oven and immediately reduce oven temperature to 350 degrees Fahrenheit.
Roast turkey for about 2 1/2 to 3 hours, until turkey breast reaches an internal temperature of 160 degrees Fahrenheit as per a meat thermometer, basting the turkey with half of the melted lemon-butter at the 2-hour mark, and the remaining lemon-butter 20 minutes later.
Remove foil from the wing tips the last hour of roasting.
Remove turkey from oven and place on cutting board; lightly cover turkey with aluminum foil and rest for about 20 to 25 minutes.
Serve with lemon-pepper gravy and sausage and cranberry dressing.