Pre-heat oven to 400°F.
Toss carrots, parsnips, sweet potatoes and baby potatoes in the olive oil, salt and dried sage leaves. Spread out on 1-2 sheet pans.
Drizzle pork tenderloin with olive oil and toss to coat.
Add the onion powder, garlic powder, paprika and salt, and rub into the pork.
Arrange pork tenderloin on the sheet pan.
Stir together the glaze and transfer half of it to a dish and set it aside (to be served with the meal). The remaining glaze will be used to brush on the pork. Use a silicone basting brush to gently brush onto the surface of the pork.
Bake for 20 minutes, then remove the sheet pans from the oven. Stir up the veggies, flip the pork, and baste with additional glaze. Scatter the apple slices over the sheet pan.
Return to the oven and bake for another 15-20 minutes, until pork reaches an internal temperature of 145°F (medium rare) or 150°F (medium).
Check if the vegetables are cooked through; if you find they still need more time in the oven, remove the pork tenderloin to a cutting board to rest while the veggies cook for longer.
Serve the pork with reserved glaze (do not use the glaze you basted the raw pork with).