Heat the air fryer to 180C. Put the leeks and rosemary in a small casserole dish and sit the sausages on top. Drizzle over the oil and cook for 10 mins in the fryer until the sausages are browned on top and the leeks have softened.

Lift out the sausages and tip the tomatoes, purée, lentils and stock into the dish. Put the sausages back with the browned side facing down. Cover and cook for a further 10 mins, until the leeks are tender.

Uncover and cook for a final 5 mins until the sausages are nicely browned. Sprinkle over the parsley and serve with a dollop of mustard and some crusty bread or creamy mash.