1 2- to 2½-pound boneless pork top loin roast (single loin)
Fresh rosemary sprigs (optional)
Preheat oven to 325°F. In a small bowl, combine brown sugar, thyme, chili powder, snipped or dried rosemary, and cayenne pepper. Sprinkle brown sugar mixture evenly over roast; rub in with your fingers.
Place roast on a rack in a foil-lined shallow roasting pan. Insert an oven-going meat thermometer into center of roast. Roast for 1¼ to 1½ hours or until thermometer registers 155°F. Cover with foil and let stand for 15 minutes. The temperature of the meat after standing should be 160°F. If desired, garnish with rosemary sprigs.
To make ahead: Prepare as directed through step 1. Cover and chill for up to 24 hours. Preheat oven to 325°F. Continue as directed in step 2.