Pork and Green Tomatillo Stew

2 tablespoons extra virgin olive oil

700g (1 1/2lbs) boneless pork shoulder or neck, cut into 3-inch chunks

salt and freshly ground black pepper

2 large celery sticks, finely diced

175g (6oz) red onion, finely diced

2 medium sized carrots (175g/6oz), peeled and chopped into 1cm (1/2 inch) cubes

1 red chilli, seeded and finely diced

2 garlic cloves, crushed

2 teaspoons medium hot chilli powder

1 tablespoon roasted and ground cumin

1 tablespoon marjoram, chopped

450ml (16fl oz) homemade chicken stock

450g (1lb) potatoes, peeled and diced

1 x 400g (14oz) tin chopped tomatoes

450g (1lb) green tomatoes or tomatillos—husked, rinsed and cut into 2.5cm (1 inch) dice

1 tablespoon chipotle in adobo, chopped

chopped coriander, for garnish

corn tortillas, for serving