Heat the olive oil in a large, deep, heavy-based pan over medium–high heat. Add the chicken and sprinkle it with salt and pepper. Cook for 3–4 minutes, tossing regularly until browned all over. Remove the chicken and set aside (it will continue cooking in the stew).
Add the water to the pan and stir to scrape up any tasty bits stuck to the bottom of the pan.
To the same pan, add the onion, garlic, celery and carrot. Cook, stirring, for 3–4 minutes until slightly softened.
Add the white wine and cook, stirring, for 1–2 minutes, or until most of the liquid has evaporated.
Add the butter and cook for 1 minute, or until melted, then add the flour, stirring for 1 minute or until the flour has dissolved and formed a paste around the vegetables.
Return the chicken to the pan. Add the chicken stock, dried thyme, potatoes and Worcestershire sauce. Bring to the boil, then reduce the heat to low and simmer, uncovered, for 15–18 minutes or until the vegetables are tender and the soup has thickened.
Turn the heat off. Add the cream and parmesan (if using), followed by the parsley. Stir to combine.
To serve, divide the stew among four bowls, top with extra parsley and season again with salt and pepper if needed. Serve with the crusty buttered bread on the side.
