Preheat the oven to 400 degrees F. Toss the broccoli, onion, ginger, garlic and orange with 2 tablespoons vegetable oil, 3/4 teaspoon salt, and pepper to taste in a shallow baking dish. Set aside.
Pat the pork dry and sprinkle all over with the five-spice powder, 1 teaspoon salt, and pepper to taste. Heat the remaining 2 teaspoons vegetable oil in a large skillet over medium-high heat. Add the pork and sear, turning, until golden brown on all sides, about 8 minutes.
Add the pork to the baking dish with the broccoli-orange mixture and roast until a thermometer inserted into the center of the pork registers 145 degrees F, 15 to 20 minutes. Transfer the pork to a cutting board and let rest 5 minutes before slicing. Meanwhile, return the broccoli-orange mixture to the oven and roast 5 more minutes. Serve the pork with the roasted broccoli and orange wedges.