This is based on a dish chef Henrique Sá Pessoa serves at his outpost in the Mercado do Ribeira, which is both a food market and a hub where local chefs serve small versions of their most famous dishes from little hatches around the edges of the building. Diners eat at long refectory tables, and it’s a chance for visitors to sample lots of classic Portuguese dishes in one go (although I prefer visiting the individual restaurants themselves for a less deafening and frenetic experience).
Henrique gave me hours of his time, kindly and patiently sharing his knowledge of Portuguese food. He also served me a wonderful pork belly dish which he’ d cooked sous-vide before roasting. This is inspired by it; for the real deal you should visit his restaurant, Alma.
Pork, especially fatty belly, is used a lot in Portugal, although it is often stewed rather than roasted. If you like heat, rub a teaspoon or so of ground piri piri chillies all over the meat and fat, or slather the meat with a couple of tablespoons of Piri Piri Sauce, before cooking.