Peel the potatoes and cut them into bite-sized bits.
Finely chop the carrot, celery, onion, chilli, red pepper and garlic.
Heat some olive oil in a large pan and sauté the chopped vegetables until tender, then the add the tomato purée and herbs.
Stir for a minute, the add the potatoes. Add some water, enough to cover everything well and add the stock pot and bay leaf.
Bring to the boil and cook for 15 minutes or until the potatoes are tender and you have a nice, thick sauce.
Meanwhile cut the fish into small chunks (you can remove the skin, if preferred).
Add the cavolo nero to the stew, then place the salmon pieces on top.
Season with salt and pepper, then put a lid on and steam for 3-5 minutes.
Carefully stir through, then serve.