1Rinse pork tenderloin and pat dry. Using a small sharp knife, cut away sinew ( this is also called silver skin) from pork. If left on, this will shrink the meat and make it tough.
2In a large Ziploc bag, combine olive oil, lemon juice, zest, garlic, sage, poultry seasoning, onion powder, and salt. Add tenderloin to bag and coat with the marinade. Squeeze out all the air and seal.
Marinate in the refrigerator 2 to 4 hours.
3Remove tenderloin from bag and discard marinade. Blot with paper towel. Sprinkle salt and pepper all over.
4Preheat oven to 400 degrees.
Heat 2 tablespoons oil in a large oven-proof sauté pan over medium-high heat.
Brown tenderloin in oil on all four sides.
Place in the oven and roast for 20 minutes, or until internal temp is 145 degrees.
Transfer to serving plate, cover loosely with foil, and let rest for 10 minutes.
5While meat is resting, make a pan sauce.
Discard oil from pan, reserving 1 tablespoon. Heat pan over medium high heat. Add 1 cup low sodium chicken stock. Bring to a boil, stirring with a wire whisk to loosen up all the brown bits from the bottom of the pan.Reduce heat to medium.
Combine 1 teaspoon cornstarch with 1 teaspoon cold water. Whisk cornstarch mixture into sauce and cook until thickened.
Spoon sauce over sliced pork roast.