Cook pre-cut pork hocks in a large pot filled with salted boiling water for 20 minutes.
Preheat oven to 160°C (325°F). Heat olive oil in a pan and brown onions, carrot and tomatoes for 2 to 3 minutes. Add dried basil, garlic and tomato paste, then transfer to an ovenproof dish with a lid.
Lay well-drained hocks over top, add chicken broth, season and cover. Cook for 1 hr 25 min to 1 hr 30 min, or until the meat becomes very tender.
While hocks are cooking, prepare gremolata. Combine zests, parsley and garlic. Set aside.
Serve hocks with a bit of sauce and top with a spoonful of gremolata.
This recipe also works well with pork cubes. Use 750 g to 1 kg (1 1/2 - 2 lb.) of stewing cubes. Omit the pre-cooking in boiling water step.