Preheat oven to 225°F.

In a small mixing bowl combine salt, pepper, brown sugar, vinegar, paprika, garlic and onion; set aside.

Lightly score the top of the New York strip loin roast in a 1-inch crosshatch pattern, about a half-inch deep. Rub roast all over with the spice mixture.

Line roasting pan with foil; top with rack and seasoned roast. Roast 2 hours, or until internal temperature reaches 110°F. Remove roast from oven, tent with foil and increase oven to 500°F.

Remove foil, return roast to preheated oven and cook an additional 10-15 minutes or until internal temperature reaches 125°F for medium rare. Remove from oven, tent with foil and allow to rest for at least 15 minutes before slicing thinly to serve.