Preheat the oven to 375. Line a baking sheet with parchment paper (or aluminum foil, lightly sprayed with nonstick spray).
Combine the onion powder, garlic powder, dried oregano, paprika, brown sugar and pepper in a small bowl.
Rub the spice mixture on the pork tenderloin and lay the tenderloin on the prepared baking sheet.
In a large bowl, toss the cut-up vegetables with 1 teaspoon of olive oil, 1 tablespoon of mustard and the rosemary.
Spread the vegetables in a single layer on the same baking sheet, next to the pork.
Put the whole thing in the oven and bake for about 30 to 35 minutes. It's ready to eat when the pork's internal temperature registers 160 °F on a meat thermometer.