Preheat your oven to 400°F. Remove the silver skin from the pork tenderloin for even cooking and better texture. Pat the pork very dry with paper towels to ensure a good sear later.
In a small bowl, combine the soy sauce, minced garlic, maple syrup, Dijon mustard, 1/4 teaspoon kosher salt, and 1/4 teaspoon black pepper. Mix well and set aside for brushing onto the pork later.
In another small bowl, combine the dried oregano, dried rosemary, garlic powder, paprika, dried thyme, 1/2 teaspoon kosher salt, and 1/2 teaspoon black pepper. Rub this mixture evenly over the entire surface of the pork tenderloin.
Heat the vegetable oil in a cast iron or other oven-safe skillet over medium-high heat. Sear the seasoned pork tenderloin on all sides, about 2 minutes per side, until browned. Remove the pork and set aside on a plate. Add the beef broth to the empty skillet, scraping up any browned bits with a wooden spoon, and cook until the broth reduces by half. This develops extra flavor for the sauce and keeps the pork juicy.
Return the seared pork tenderloin to the skillet. Brush it with about half of the maple mustard sauce from Step 2. Place the skillet in the preheated oven and bake uncovered for 15–20 minutes, or until the thickest part of the pork registers 137–140°F on a meat thermometer. I always trust an instant-read thermometer so I never overcook the pork.
After baking, brush the pork with the remaining maple mustard sauce. Broil under HIGH heat for 1–2 minutes, just until the sauce is golden brown and caramelized for a sticky, flavorful finish.
Allow the pork to rest out of the oven for 5–10 minutes before slicing into 1/2-inch thick pieces. Sprinkle with minced fresh parsley if you like, and drizzle with the pan juices and drippings for extra flavor. I like to wait the full 10 minutes so the pork stays juicy.