Preheat oven to 230 degrees celcius.
Rub oil onto pork roast. In a small bowl, stir together salt, pepper, garlic powder, onion powder, and paprika. Sprinkle seasoning mixture onto pork roast. Place fatty side up in a roasting pan or large cast iron dutch oven.
Roast, uncovered, in the preheated oven for 30 to 45 minutes. Reduce the oven
temperature to 180 degrees and continue cooking an additional 1 hour.
Remove roast from oven and place the onion chunks, carrots, and potatoes around the
meat. Pour apple juice on vegetables. Season vegetables with salt and pepper.
Place rosemary sprig on top.
Cook an additional 1 to 1 1/2 hours, or until vegetables are tender and meat shreds
easily with a fork. Season vegetables with additional salt and pepper to taste
and serve hot.