Sprinkle the pork really well with salt, pepper and paprika. Tie the pork with kitchen twine (or you can purchase it tied from the butcher). Set a roasting rack inside of a roasting pan and place the pork on the rack. Roast for 3 hours, basting periodically.
After 3 hours remove the pork from the oven and gently lift the rack off the pan. Scatter the carrots, potatoes, onions and garlic in an even layer and season with salt and pepper. Place the rack and pork back on top of the vegetables and continue to roast until the vegetables are caramelized and the pork is tender and yielding, another 2 to 3 hours.
Remove from the oven and allow the pork to rest for 15 minutes while you make the pan gravy.
Remove the vegetables to your serving platter and place the pan over the stove-top burner on medium heat. Add the flour and stir to combine with the fat. Gradually stir in the stock, being sure to scrape the bottom of the pan for brown bits. Bring to a simmer so the gravy can fully thicken, and then stir in the parsley. Serve the pork with lots of vegetables and the pan gravy on and around.