In a small bowl, combine the salt, pepper, garlic, rosemary, and 1 tablespoon of the olive oil. Mix well and spread over the tenderloin. Cover and refrigerate for 2 hours or overnight.
Preheat oven to 400 degrees. Line a baking sheet with foil and spray with nonstick spray.
Brush most of the seasoning off the tenderloin. Heat the remaining oil in a large skillet on high. Once the oil is hot, cook the tenderloin on all sides until golden brown. Place the seared pork tenderloin on the prepared pan and bake for 45 minutes or until cooked through. Let the pork sit for about 15 minutes before slicing and serving, this will help the tenderloin stay juicy!