Let the tenderloin cool before serving. Pan-roasting pork tenderloin Preheat your oven to 425ºF and coat an ovenproof skillet with oil. Sear the tenderloin over medium-high heat until it’s brown on all sides. Roast the tenderloin for 15 to 20 minutes until the internal temperature reads 145ºF.Let it cool before serving. Stuffed pork tenderloin To butterfly the tenderloin, trim the silver skin with a thin sharp knife.rilling pork tenderloin Always cook the tenderloin over indirect heat. Depending on its size, it usually takes 20 to 30 minutes over medium-high heat. Flip the tenderloin every 4 minutes until the internal temperature reaches 135ºF to 140ºF.