01 - Preheat your oven to 400°F (200°C). Thoroughly pat the pork tenderloin dry using paper towels. Season the entire surface generously with salt and freshly ground black pepper.
02 - In a large, ovenproof skillet, heat the olive oil over medium-high heat. Sear the seasoned pork tenderloin on all sides until a golden-brown crust forms, approximately 6 minutes in total. Remove the pork from the skillet and set aside.
03 - Reduce the skillet's heat to medium. Add the pomegranate juice, honey, balsamic vinegar, Dijon mustard, minced garlic, ground cinnamon, and optional red pepper flakes to the same skillet. Bring the mixture to a gentle simmer and cook, stirring periodically, until it has reduced by half and achieved a slightly thickened consistency, about 8 to 10 minutes.
04 - Return the seared pork tenderloin to the skillet. Turn the pork to ensure it is evenly coated with the prepared glaze. Carefully transfer the entire skillet to the preheated oven. Roast for 15 to 18 minutes, or until the internal temperature of the pork reaches 145°F (63°C) on a meat thermometer.
05 - Remove the pork from the oven and allow it to rest for 5 minutes before slicing. Drizzle the sliced pork with any remaining glaze from the skillet.
06 - Garnish the finished dish with fresh pomegranate arils and chopped parsley just before serving.