Preheat the oven to 375 degrees F. 

Meanwhile, in a small skillet over low heat, melt the butter. Add the onion and cook, stirring occasionally, until tender, about 5 minutes. Transfer the onion to a large bowl and add the bread, peach, cheese, parsley, thyme, 1/4 teaspoon salt and pepper. Slowly pour in the broth and stir until combined. Set aside. 

Butterfly the pork by cutting it lengthwise to within 1/2-inch of the bottom side. Do not cut all the way through. Open it out and pound to 8x10-inch rectangle, fat side down. Spread the stuffing mixture over the pork, leaving about a 1-inch border at the edges. Roll the pork up, jelly-roll style, and arrange it seam side down. Spread the mustard all over the meat. 

In a small bowl, combine the brown sugar, paprika and 1 teaspoon salt. Rub the mixture all over the roast, then wrap the bacon slices around the roast. Tie the roast with butcher's twine at each slice of bacon. Arrange the pork, seam side down, in a roasting pan and roast until the internal temperature of the pork reaches between 145 degrees F. (medium rare), with a 3-minute rest, and 160 degrees F. (medium), about 1 hour and 15 minutes, basting halfway through. 

Let rest 15 minutes before slicing and serving