Melt butter in large nonstick skillet over medium heat. Add onion and pepper, and sauté 6 to 8 minutes or until tender. Add cider and next 3 ingredients, and bring to a boil; reduce heat, and simmer 2 minutes. Remove from heat, and let stand 5 minutes. Stir in stuffing mix, and set aside.
Butterfly 1 pork loin by making a horizontal cut (about one-third down from top) into 1 side of pork, cutting to within 1/2 inch of other side. (Do not cut all the way through roast.)
Unfold top cut piece, open, and lay flat. Butterfly and repeat procedure on opposite side of remaining two-thirds portion of pork loin, beginning at top or bottom of inside cut.
Place pork between 2 sheets of heavy-duty plastic wrap; flatten to 1/2-inch thickness using a mallet or rolling pin. Rub pork loin completely with 1 tablespoon olive oil, and sprinkle both sides evenly with half of Spice Rub. Spread half of stuffing mixture on pork, leaving a 1/2-inch border. Roll up roast, and tie with kitchen string at 2-inch intervals.
Repeat with remaining pork loin, oil, Spice Rub, and stuffing mixture.
Arrange apple wedges in a single layer in the bottom of a 13- x 9-inch roasting pan. Place roasts, seam sides down, on apples.
Bake at 450° for 25 minutes. Reduce temperature to 425°; bake 25 more minutes or until a meat thermometer inserted into thickest portion registers 155°. Remove from oven; let stand 15 minutes or until thermometer reaches 160° before slicing. Discard apples. Serve pork with Cider Sauce.
Note: For testing purposes only, we used Pepperidge Farm Cornbread Stuffing mix.