Drain the belly pork and rinse under cold running water. Put in the bottom of a deep casserole dish, preferably an earthenware one. Mix together the onion, garlic, tomato puree, parsley and sugar, and put this mixture in a layer on top of the pork.

Drain the beans and rinse under cold running water. Add to the casserole. Sprinkle with plenty of pepper and stir in enough water to cover.

Cover the casserole with a lid and bake in a very cool oven (140°C/275°F or Gas Mark 1) for 5 hours or until the beans are tender.

Check the water level occasionally, adding a little more water if the casserole becomes too dry. If you want to leave the beans to cook overnight, put into an even cooler oven (100-125°C/225-250°F or Gas Mark 1/4 - 1/2).

When cooked, remove the belly pork from the casserole and chop into bite-sized pieces. Stir back into the casserole and adjust seasoning before serving.