Preheat oven to 425°F (220°C) and line a large baking sheet with parchment paper.
In a small bowl, mix the Dijon mustard with half of the olive oil. Set aside.
Place pork, broccoli, and potatoes on the baking sheet. Drizzle with remaining olive oil, then sprinkle with garlic powder, onion powder, salt, and pepper.
Toss everything to coat evenly, then spread out in a single layer on the baking sheet.
Drizzle the mustard mixture over the pork and vegetables.
Roast in the preheated oven for 25 minutes, or until the pork is cooked through and the vegetables are tender.
Serve immediately, garnished with additional black pepper, if desired.