Trim the fat and silver skin off of each pork tenderloin (see Notes) and pat dry with paper towels. Rub 1 tablespoon oil over the tenderloins.
In a small bowl, combine the salt, garlic powder, onion powder, and pepper. Sprinkle all over each piece of pork, rubbing with your hands to evenly coat.
Heat the remaining 2 tablespoons oil in a large cast-iron skillet over medium-high heat. Add both pork tenderloins to the skillet and brown on all sides, about 1 to 2 minutes per side.
Place the skillet in oven and bake until a meat thermometer inserted in the thickest portion of each tenderloin reaches 145°F, about 20 minutes. Transfer the pork to a cutting board and cover with foil. Let rest for 5 minutes before slicing.
Notes
Pork will still be pinkish when done, very juicy, and tender.
Don’t skip patting dry the tenderloins with paper towels. It’ll help the oil and seasoning stick better to the tenderloins.
Allow the pork to rest before cutting will allow the moisture to redistribute and keep the tenderloins juicy. If you cut open the pork immediately, the juices will end up all over your cutting board.
Be careful not to overcook the pork. As pork is lean, it’s easy to overcook, I highly recommend using a meat thermometer to check for doneness instead of relying on the timing itself.
By searing the pork before baking, it gives the exterior a nice brown crust while adding flavor and sealing in the juices.
Do not skip removing the silver skin. It is extremely chewy and tough, causing it to be unpleasant to eat. To trim silver skin, use a sharp, narrow-bladed knife and slip the blade just under the silver skin, making a “tab” to hold on to. Holding the tab taut with one hand, run the blade under the thick membrane, keeping it angled away from the meat until you reach the end of the membrane.