1. Prepare Pork Loin: Bring first 4 ingredients and 1 cup water to a boil in a small saucepan over medium-high heat. Cook 2 minutes, stirring once. Remove from heat, and cool completely (about 40 minutes).
2. Meanwhile, butterfly pork by making a lengthwise cut down center of 1 flat side, cutting to within 1/2 inch of other side. (Do not cut all the way through pork.) Open pork, forming a rectangle, and place between 2 sheets of heavy-duty plastic wrap. Flatten to 1/2-inch thickness using a meat mallet or rolling pin. Sprinkle with 1/2 tsp. each salt and pepper.
3. Spoon fruit mixture over pork, leaving a 1/2-inch border around edges. Roll up pork, jelly-roll fashion, starting at 1 long side. Tie with string at 1 1/2-inch intervals. Sprinkle with remaining 1 tsp. salt and 1 tsp. pepper.
4. Preheat oven to 375°. Brown pork in hot oil in a large roasting pan over medium-high heat until browned on all sides (about 2 to 3 minutes per side). Place seam side down in pan.
5. Prepare Roasted Pears and Onions: Cut pears in half lengthwise, and remove core. Stir together butter and next 5 ingredients. Stir in onions; gently stir in pear halves. Spoon mixture around roast in pan.
6. Bake at 375° for 1 hour to 1 hour and 5 minutes or until a meat thermometer inserted into thickest portion of stuffing registers 135°, stirring pear mixture halfway through. Cover with aluminum foil, and let stand 15 minutes.
7. Prepare Glaze: Microwave preserves in a microwave-safe bowl at HIGH 1 minute or until thoroughly heated. Pour warm preserves over pork. Slice pork, and serve with Roasted Pears and Onions and pan juices. Garnish, if desired.
*3 firm, ripe Bartlett pears may be substituted. Core each pear, and cut into 4 wedges.
**Sugar may be substituted.