Preheat oven to 400 degrees. Line a baking dish with aluminum foil. Wash your hands well, then set out a few sheets of paper towel and pat the pork tenderloin dry and set on paper towel. With hands press the brown sugar onto the pork tenderloins and then sprinkle each tenderloin with salt and pepper. In a small bowl mix together the balsamic vinegar and the extra virgin olive oil.