Directions:

1. Pork Preparation: Combine water, brown sugar and kosher salt for brine. Mix until dissolved. Place pork loin in deep roasting pan. Cover thawed pork loin completely with brine. Refrigerate for 8 to 12 hours to marinate. Preheat oven to 375°F. Remove pork from brine. Rinse well and pat dry. Place pork in oven. Roast for 1 to 1½ hours. Minimum internal temperature should be at least 155°F. Remove from oven. Loosely cover with foil and rest for 30 minutes. Slice the pork loin thin for sandwiches. Refrigerate any additional pork not used for sandwiches.
2. Mustard Peach Glaze: Combine and mix all ingredients in a mixing bowl.
3. Caramelized Onions: Peel and julienne onions. Heat olive oil. Blend oil in large sauté pan or skillet on medium heat. Add onions; stirring occasionally, sauté until onions begin to turn golden. Stir in balsamic vinegar, salt and pepper; cook until golden color is achieved.
4. Sandwich Build: Place 3 to 4 thinly sliced pieces of pork loin and ¼ cup Caramelized Onions in pan and heat through for about 1½ to 2 minutes. Add 1 tablespoon Mustard Peach Glaze to the pork. Allow to caramelize for 1½ to 2 additional minutes. Place 1 slice of Swiss cheese on top on pork mixture to melt. Place pork on heel of toasted roll. Top with crown of roll. Serve immediately.