Preheating and Preparation: Set the oven temperature to 350°F (180 C). Wash the pork tenderloin thoroughly and pat it dry with paper towels. Season generously with salt and black pepper.
Searing the Pork: In a heavy-bottomed skillet, heat olive oil over medium-high heat for about a minute. Brown the pork tenderloin on all sides until a golden crust forms, approximately one minute per side. Remove the pork from the skillet and set aside.
Creating the Sauce Base: Melt butter in the same skillet over medium heat. Add minced garlic and sauté for about 30 seconds until fragrant.
Developing the Favor: Stir in balsamic vinegar and your preferred dried herb blend. Cook for one minute, or until the butter has completely melted and the sauce begins to thicken slightly.
Combining Pork and Sauce: Return the pork tenderloin to the skillet and coat lightly with the prepared sauce.
Oven Roasting: Cover the skillet with aluminium foil and transfer it to the preheated oven. Roast for 30 minutes. Uncover the skillet, spoon additional sauce over the pork, and then cover again. Continue roasting for another 30 minutes, or until the internal temperature reaches 145 °F (63 C).
Resting and Serving: Remove the skillet from the oven and loosely cover the pork with foil. Allow it to rest for approximately 15 minutes before slicing thinly. Garnish with fresh rosemary sprigs.