How to Make It
In a small bowl, stir 1/4 cup of the olive oil with the garlic, rosemary, salt and pepper. Rub the mixture all over the pork. Transfer the pork and marinade to a large, resealable plastic bag and refrigerate overnight.
Preheat the oven to 400°. Let the pork stand at room temperature for 30 minutes. Brush off as much of the marinade as possible. In a large ovenproof skillet, heat the remaining 2 tablespoons of olive oil until shimmering. Add the pork to the skillet and cook over moderately high heat until browned all over, about 5 minutes. Transfer the pork to the oven and roast for 40 to 45 minutes, until golden and a thermometer inserted in the thickest part registers 135°. Transfer the roast to a work surface or carving board and let rest for 15 minutes before thinly slicing and serving.