Remove the silver skin from the pork tenderloin with a sharp knife. Slice into 1-inch thick medallions.
Season with salt, pepper, paprika, and garlic powder.
Stovetop: Heat olive oil in a large skillet over medium-high heat. Sear pork medallions for 2 minutes on each side. They should be sizzling when they touch the oil. If they don't sizzle right away, remove the pork and allow the oil to heat up before re-adding. Scrape the bottom of the pan to loosen any browned bits. Add barbecue sauce and vinegar to the pan. Toss the medallions in the sauce and let simmer for 3-5 minutes, or until the pork reaches an internal temperature of 145 degrees Fahrenheit using an instant read meat thermometer.
Grill: Heat grill to medium-high heat, about 400 degrees Fahrenheit. Place rubbed pork medallions directly on an oiled grate. Add BBQ sauce and apple cider vinegar to a small bowl, and whisk to combine. Grill the medallions for 3-4 minutes per side. Then, grill and baste with the BBQ sauce for an additional 1-2 minutes per side, or until the pork reaches an internal temperature of 145 degrees Fahrenheit using an instant read meat thermometer.
Garnish with chopped parsley, if desired. Serve and enjoy.
Notes
If using a small skillet, you may need to sear the pork in batches!