Preheat your oven to 400°F (200°C).
Trim any excess fat from the pork tenderloin and pat dry.
In a small bowl, combine ground cinnamon, salt, and black pepper. Rub this spice mix all over the pork.
Core and slice the apple into wedges. Peel the carrot and parsnip, then cut them into bite-sized pieces.
In a roasting pan, toss the apple and root vegetables with olive oil, a pinch of salt, and extra cinnamon if desired.
Place the seasoned pork tenderloin on top of the vegetables in the pan.
Roast in the preheated oven for about 25-30 minutes, or until the pork registers an internal temperature of 145°F (63°C) and the vegetables are tender.
Remove from oven, let the pork rest for 5 minutes, then slice and serve with the roasted apples and root vegetables.