Preheat your oven to 400 degrees Fahrenheit. Dry the pork tenderloins well with paper towels.
Mix the paprika, onion powder, garlic powder, oregano, salt, and pepper together in a small bowl. Rub this spice mix over all sides of the pork.
Heat the oil in a large frying pan over medium-high heat. Add the pork, working in 2 batches if your pan is not big enough to fit both tenderloins without them touching. Sear the pork on all sides until it is brown, about 6 minutes total. Take the pan off the heat.
Move the pork to a baking dish. If the spices left in the pan are black, wipe them away with a paper towel. Return the pan to the heat and add the beef broth. Scrape the bottom of the pan to remove any stuck-on bits then boil for 1 minute until it reduces to about ¼ cup. Pour this sauce over the pork.
Pour the apple cider vinegar over the pork then dot the top with the butter. Cover the baking dish with foil.
Bake the pork for 20-25 minutes, or until it reaches an internal temperature of 145 degrees Fahrenheit. Let the pork rest for 5 minutes before slicing it into ¼ -inch thick rounds. Pour the pan juices over the pork tenderloin slices and serve with a little minced parsley, for color.