In a skillet, fry bacon until cooked but not crisp. Remove bacon from skillet; blot on paper towel.
Dice onion in about a 1/4-inch size. Add to bacon drippings in skillet & sprinkle with salt. Cook & stir about 15 minutes or until moisture has evaporated & onion is soft.
Reduce heat; sprinkle with apple cider vinegar. Cook & stir until golden. Add brown sugar; cook & stir until golden. Cook sweet potato, peel & mash.
Preheat oven to 350 F.
Remove any ‘silver-skin’ from pork tenderloin. Butterfly tenderloin & pound carefully to make it an even thickness. Sprinkle with salt & pepper. Spread cut side evenly with mashed sweet potato & top with caramelized onion & crumbled bacon .
Starting on the short end, roll tenderloin & place seam side down on a lightly greased piece of foil. Place on a baking sheet & cup foil corners to resemble a dish. Brush tenderloin with Fig Balsamic Olive Oil Vinaigrette (or just use oil).
Roast about 45 minutes or until meat thermometer reaches 160 F. If you prefer you can roast the tenderloin 8-10 minutes more.