01 -
Trim the silver skin from the pork tenderloins using a sharp boning or paring knife. Discard silver skin after removal.
02 -
In a small bowl, combine 1.5 teaspoons kosher salt, 0.25 teaspoon black pepper, garlic powder, onion powder, dried thyme, paprika, and poultry seasoning. Rub mixture evenly onto pork tenderloins. Allow to marinate for at least 45 minutes or up to several hours. Remove from refrigerator 30 minutes before roasting to bring to room temperature.
03 -
Heat 1 tablespoon olive oil and butter in a wide skillet over medium heat. Add sliced onions and a generous pinch of kosher salt. Cook for 3–4 minutes until softened, then reduce heat to medium-low. Stir occasionally and cook for about 45 minutes until onions are deeply golden and tender. Add extra olive oil if necessary to prevent sticking. Transfer caramelized onions to a 23x33 cm baking dish.
04 -
Preheat oven to 200°C. In a bowl, whisk together maple syrup, grainy mustard, minced garlic, balsamic vinegar, Worcestershire sauce, remaining 0.5 teaspoon kosher salt and 0.25 teaspoon pepper. Set aside.
05 -
Heat remaining 1 tablespoon olive oil in a skillet over high heat. Sear tenderloins on all sides until evenly golden. Transfer seared meat to baking dish atop caramelized onions.
06 -
Deglaze the skillet with beef broth, bringing it to a simmer and scraping any browned bits with a wooden spoon. Add maple-mustard mixture, return to simmer, and cook for 3–4 minutes until sauce reduces slightly. Pour over tenderloins in the baking dish.
07 -
Roast in the preheated oven for 15–20 minutes, or until internal temperature reaches 63°C. Transfer tenderloins to a cutting board and loosely tent with foil. Rest for 10–15 minutes before carving.
08 -
Cut pork into medallions. Arrange caramelized onions on a serving platter, top with sliced pork, and spoon pan juices over. Serve immediately.