Place the oil in a large saucepan and place over a medium heat. Add the chorizo and cook gently for 5 minutes to allow the chorizo to release it's oils. Then add the onions, leek, carrot, celery and butternut squash and cook for 5 minutes.
Add the garlic, peppers, chilli and a teaspoon of sea salt to the pan and cook for a further 2 minutes.
Sprinkle over the smoked paprika and stir through the vegetables, cook for a minute. Then add the sherry, turn the heat up and cook the sherry out for around 3-4 minutes.
Next add the chicken stock, butter beans, tomato puree, thyme and bay leaf. Stir thoroughly to combine and bring to the boil before turning down to a gentle simmer. Cover the pan with a lid and simmer gently for 45 minutes. Remove the lid and continue to simmer for a further 30 minutes to allow the sauce to reduce.
Meanwhile place a large frying pan over a high heat, add another tablespoon of sunflower oil to the pan. Season the chicken breasts with salt and pepper and place in the frying pan skin side down. Cook for around 3-4 minutes until the skin is golden and crispy, before turning and cooking for a minute on the other side.
Place the chicken breasts skin side up on a large roasting tray and place in an oven at 180CFan for 12-14 minutes to cook the meat right through. Then set aside somewhere warm to rest for 5-10 minutes.
When ready to serve, stir the parsley through the stew and season with salt and pepper to taste. Spoon the stew into individual warm bowls.
Place the roasted chicken breast on top of the stew with the crispy skin on top. Serve immediately.