Preheat oven to 375 degrees. Trim any excess fat, and rinse pork under cold water, set on paper towels and pat dry. Season all sides with salt and pepper to your own taste. Heat oil in large frying pan over medium-high heat. Get the pan nice and hot! Place pork into pan, and brown/sear on all sides, don't forget the ends. About 2-3 minutes per sides, if your pan is very hot. Check so you don't burn it or under sear it. Remove pork from pan and set on a plate. Turn down heat to medium, and add the balsamic vinegar. Using a plastic spatula, scrape any bits off of the bottom of the pan, that's the good stuff! Stir in dark brown sugar (can sub regular brown sugar, but dark is better), using spatula and keep scraping the bottom and stirring the sauce constantly. Don't worry, it's very easy. Do this for about 2-3 minutes til sauce has reduced and is thickened. Just don't do it too long, because it still has to bake and you don't want to end up with thick burnt tar to roof your house with! Turn heat off. Place pork back into the skillet and turn several (4-5) times to coat/glaze all sides, ending with it bottom-side up. (Fat side is bottom for this one.) Sprinkle bottom side evenly with 1/4 teaspoon (half) the thyme, using your fingers crushing it as you sprinkle. Sprinkle with half the garlic powder, (1/4 teaspoon also). Place pork, newly seasoned-side down into (greased) shallow roasting or baking dish. Now season the top the same way. Pour remaining glaze over pork. Let rest 10 minutes, and keep re-glazing with the sauce in the pan. (Just tilt the pan and spoon it over.)Place in oven and roast for 30-35 minutes. (35 if slightly larger). Remove from oven, loosely cover with foil, and let rest for 10-15 minutes. This gives you time to heat up that corn or green beans!
Remove pork from baking dish to platter, slice and plate. Stir pan juices and pour over slices. (Don't scrape the bottom or any super thick parts, though, just mostly the juices). And serve!