For a delicious alternative to the pears, substitute for a tart green apple, such as Granny Smith. Instead of rosemary alone, you could combine it with sage and thyme, for a slightly more complex flavor. To balance the naturally sweet flavors in the pork dish, bake a savory casserole of bread dressing with pork sausage, onions, and herbs. Green vegetables should be simple and along the lines of sautéed green beans with toasted almonds, or steamed and sautéed Brussels sprouts with hazelnuts.
- Preheat oven to 450 degrees F. Rub pork all over with oil. Mix rosemary, 3/4 teaspoon salt, and 1/2 teaspoon pepper in small bowl. Rub all over pork.
- Place pork, bone side down, in large flameproof roasting pan. Roast 15 minutes. Reduce oven temperature to 350 degrees F. Roast 15 minutes more. Add sweet potatoes and pears to pan, stir gently to coat with pan juices, and spread as evenly as possible around roast. Season with salt and pepper. Roast, occasionally stirring sweet potato mixture, until instant-read food thermometer inserted in center of roast reads 145 degrees F and the potatoes and pears are tender, about 1 hour more. Transfer pork to carving board. Transfer sweet potato mixture to ovenproof bowl, tent with aluminum foil, and keep warm in turned-off oven. (If needed, increase oven temperature to 400 degrees F, and continue roasting sweet potato mixture until tender, up to 15 minutes longer.) Let pork stand for 10 to 15 minutes.
- Heat roasting pan over high heat. Add cider, bring to a boil, scraping up browned bits in pan with wooden spoon, and boil until reduced to 3/4 cup, about 5 minutes. Pour into sauceboat.