Place a casserole dish or deep frying pan on a medium heat for a min then add 1 tbsp olive oil. Carefully add the chicken sausages and fry them for 6 mins, turning them over every now and then till they are browned on most sides.

While the sausages are cooking, peel and finely chop the onion. Trim the celery and finely slice it. Peel and dice the sweet potato. Peel and finely grate or crush the garlic. Finely chop the parsley stalks and leaves.

When the sausages are browned, add the onion, celery and sweet potato to the pan. Season with a pinch of salt and pepper and cook for 5 mins, stirring often, till softened. Add the garlic and half the parsley to the pan and fry, stirring, for 2 mins.

Tip the chopped tomatoes into the pan, then add the cannellini beans with the liquid from their tin. Drop in the bouquet garni (see our tip below, on how to keep the herbs together) and add 1 tsp of the sugar. Gently stir. Pop a lid on the pan (or use a baking tray if you don't have a lid) and simmer on a medium heat for 15 mins.

After 15 mins the sausages should be cooked through and the sweet potato should be tender. Check the sausages are cooked by cutting one in half. There should be no pink. Cook for a little longer if you need to.

Taste the stew and add more salt, pepper or sugar if you think it needs it. Fish out the bouquet garni and discard it. Serve the sausages and beans in warm bowls topped with the remaining parsley and a crack of pepper.