Oven-baked pork tenderloin is not a complicated dish, but it's easy to overcook the delicate meat into dry, tough medallions. Tenderloin is a lean cut, so the key is keeping it moist while it cooks. Instead of simply seasoning the tenderloin and setting it in the oven, take a few extra steps to ensure a succulent roast. Marinating the meat beforehand and baking it at the optimal temperature will help you achieve a juicy, flavorful dish.
Marinate the pork tenderloin to tenderize and impart flavor into the meat. You can use any type of marinade for your pork tenderloin. A basic marinade should have one part acid, such as vinegar or lemon juice, and one part oil, which adds moisture, distributes the flavors and promotes browning. You can then add one to two parts seasonings or aromatics such as salt, sugar, pepper, hot sauce or fresh herbs. Place the pork tenderloin in resealable freezer bag and pour the marinade over it. Squeeze all of the air out of the bag and leave it in the refrigerator for up to 24 hours, turning the bag every few hours.
Sear the tenderloin before roasting. Although searing doesn't really seal in juices, as is widely believed, it does give the tenderloin an attractive browning and caramelizes the marinade on the surface, adding more flavor. To sear, first let the pork tenderloin come to room temperature. Add a drizzle of vegetable oil into the saute pan and set on high heat. Once the pan is fully heated, add the pork, leaving it for 30 seconds to a minute on each side until the entire roast is browned.
Preheat an oven to 475 degrees Fahrenheit and place the pork tenderloin into a small roasting pan or baking dish. Roast an average-sized, 2-lb. tenderloin for about 10 to 15 minutes, or until its internal temperature comes to 140 F. Pork should be cooked to an internal temperature of 145 F, but it needs to rest for about 10 minutes before slicing, at which time the temperature will raise another 5 degrees or so. Slice the pork into 1-inch-thick slices before serving.
Serve the pork tenderloin with a flavorful gravy or sauce, if you like, to impart a final dose of moisture. Consider flavors that complement pork, such as a sweet and spicy mustard-based sauce, or an apple-based chutney.