Preheat oven to 425°F (220°C)
Pat pork loin dry with paper towels
Season all sides with salt and pepper
Add optional rub: garlic powder, onion powder, paprika, dried thyme, rosemary, or brown sugar
Sear (optional): heat a skillet with oil over medium-high heat and brown the pork loin on all sides, 2–3 minutes per side
Place pork loin on a rack in a roasting pan (or directly in the pan)
Insert an oven-safe meat thermometer into the thickest part of the loin
Roast until internal temperature reaches 145°F (63°C), about 20–30 minutes depending on thickness
Remove from oven and tent loosely with foil
Rest 10–15 minutes before slicing
Slice against the grain
Optional glaze (apply last 10–15 minutes): brush with honey-mustard, BBQ, maple-balsamic, or apple cider glaze