Lean cuts are tricky because they both lack the moist-making marbling of fattier cuts while also being relatively compact and quick-cooking—a double hazard to overdone meat. This recipe uses a fail-proof trick for a tender, juicy pork loin: Wrap the whole thing in parchment paper after sprinkling on some aromatics. Both cooking and letting it rest in the parchment is key; this allows the juices to reabsorb and evenly distribute throughout the loin. Then, all you have to do is unwrap, slice, and serve your lovely, succulent roast!
Heat the oven to 400°F. Rub the pork with oil and season generously with salt and pepper. Mix peppercorns and brown sugar in a small bowl and coat the pork lightly on all sides.
Place the pork on top of a 12-inch x 14-inch piece of parchment paper with the loin aligned along one long end of the parchment. Top the pork with sage leaves and roll it up tightly in the parchment. Twist the ends closed and tie each end tightly with butcher’s twine.
Place on a rimmed baking sheet and roast until an instant-read thermometer inserted into the thickest part of the pork (through the parchment) reads 140°F, about 20 to 25 minutes. Remove from the oven but keep the pork wrapped. Let rest for 10 minutes, unwrap, and thinly slice. Drizzle with any juices accumulated in the parchment and serve.