Place the balsamic vinegar in a small sauce pan over medium heat. When the vinegar begins to boil, adjust the heat to a simmer.
Cook the vinegar until it is reduced to 1/4 cup. Set aside.
Place a large skillet in the oven and preheat to 375°F.
When the oven is at temperature add the oil to the pan and swirl to coat.
Add the tenderloin and sprinkle the salt and pepper over the tenderloin.
Roast the pork, turning 2 or 3 times, for about 15 to 20 minutes.
Remove the pork from the oven and let rest for about 2 minutes.
Slice and serve topped with the balsamic glaze.
