Heat the oven to 400°. Season the pork generously with the ground fennel, salt and pepper.
Heat a large sauté pan over medium-high heat, lightly oil the pork, place it in the hot pan and brown it evenly on all sides.
Meanwhile, using the rosemary, garlic and fennel, create a nest in a roasting pan. Transfer the pork to the roasting pan and place it in the heated oven.
Allow the pork to roast to an internal temperature of 140°. Remove the pork from the oven, tent loosely with foil and allow to rest for 15 minutes. Carve the pork and serve with the roasted rosemary, garlic and fennel.