For the chilli, put the first eight ingredients in a food processor, blitz until finely chopped, then transfer four tablespoons of the mixture to a small bowl.
Put two tablespoons of oil in a large, heavy-bottomed pan on a medium-high heat and, once hot, fry the pancetta for a minute or two, until it starts to brown. Add the diced pork and fry, stirring once or twice, for six minutes, until lightly browned all over. Add the blitzed ingredients and a teaspoon and a half of salt, and fry for eight minutes more, stirring every now and then. Add the two lime halves and stock, bring to a simmer, then turn the heat to medium-low, cover and leave to simmer for 90 minutes. If it looks a bit dry add a little more water as needed.
Meanwhile, make the cornbread. Heat the oven to 190C (180C fan)/390F/gas 6, and grease and line a 22cm cake tin. Put all the cornbread ingredients and three-quarters of a teaspoon of salt in a blender or food processor, and blitz until everything is well combined. Pour the mix into the prepared tin and bake for 25 minutes, then turn down the heat to 170C (160C fan)/350F/gas 4 and bake for six minutes more.
Add the last two tablespoons of oil to the reserved jalapeño and onion mixture and stir into the chilli with the chopped coriander, then serve direct from the pan with the warm cornbread alongside.