Heat oven to 450 degrees F.
Prepare the stuffing mix according to package instructions in a bowl.
Place roast, fat side up, on a clean surface. With a sharp knife, cut along length of pork loin without cutting all the way through. Open up pork like a book. Spoon stuffing down center of pork. Close pork over stuffing. Tie up loin with kitchen twine, spacing twine about every 1 1/2 inches. Rub pork with 1 tablespoon olive oil. Stir together the flour, salt and pepper in a small bowl. Rub the seasoned flour mixture evenly over the pork loin.
Toss together sweet potato chunks and the remaining 2 tablespoons olive oil in a roasting pan; spread out evenly over bottom of pan. Place the tied pork loin, fat side up, on top of the potatoes in the roasting pan.
Roast in 450 degrees F oven for about 10 minutes. Reduce oven temperature to 350 degrees F. Continue to roast for 55 to 60 minutes or until instant-read meat thermometer inserted into the pork, but not in the stuffing, registers 150 to 155 degrees F and potatoes are fork tender. Let the pork rest for about 15 minutes; temperature of pork should increase to 160 degrees F. Keep the sweet potatoes warm. Remove the twine from the pork loin before slicing. Serve with potatoes.
Recipe courtesy of Family Circle Magazine