Mix brown sugar and soy sauce in a bowl. Place pork loin in a plastic bag and pour mixture on top. Roll tenderloin in mixture, covering it completely. Marinate meat at least 3 hours or overnight in fridge.
Preheat oven to 350°. Place pork loin on a slotted baking sheet with a drip pan underneath. Reserve marinade. Wrap a piece of bacon around the end of the tenderloin and secure with a toothpick. Repeat until the entire loin is wrapped. Drizzle remaining marinade over the meat. Place on center rack in oven and bake 50-60 minutes. Continue to baste the loin with the marinade using a brush or turkey baster. With about 10 minutes of cooking time left, lightly dust the top of the loin with white sugar and allow it to caramelize.
Remove meat from over and rest for 10 minutes. Slice crosswise.
Recipe by Steve & Michelle Ellis, Gray Court