From America's Test Kitchen Season 6: Pork Chops and Tenderloin
Because pork tenderloins are so lean, they cook relatively quickly and are therefore a good choice for an easy-to-prepare meal. But that same leanness means there’s also less flavor. Grilling is often used to add more flavor, but we wanted an indoor preparation for pork tenderloins that would deliver a flavor boost to this quick-cooking roast.
Simply roasted in the oven, the pork tended to dry out and never achieved the dark brown crust we wanted. We got that crust when we seared the tenderloins on the stovetop—but then the pork wasn’t cooked through. A combination of searing the meat in a skillet, then transferring the pork to the oven to finish cooking, produced a flavorful crust and well-cooked meat. The browned crust added some flavor, but we wanted more. A dry rub of just salt and pepper, left on for half an hour before searing, provided enough seasoning and further encouraged a browned crust, and a pan sauce made with the browned bits left from sautéing was an additional flavor boost. Not only were these pork tenderloins delicious; they were also on the dinner table in about half an hour.
"Enhanced" pork--pork that has been injected with water, salt, and sodium phosphate--does not brown well owing to the extra moisture. We prefer natural pork tenderloins that have not been injected. Because two are cooked at once, tenderloins larger than 1 pound apiece will not fit comfortably in a 12-inch skillet. Time permitting, season the tenderloins up to 30 minutes before cooking; the seasonings will better penetrate the meat. The recipe will work in a nonstick or a traditional (not nonstick) skillet. A pan sauce can be made while the tenderloins rest (recipes follow); if you intend to make a sauce, make sure to prepare all of the sauce ingredients before cooking the pork.