Season the chicken with ½ teaspoon of salt and ½ teaspoon of black pepper, then toss in the flour to evenly coat.

In a large saucepan over moderate heat, cook the onions in half the butter for 10 minutes until soft, then stir in the bay leaves and allspice.

Meanwhile, cook the chicken in the olive oil in a large frying pan over high heat for about 5–7 minutes until beginning to colour and just cooked through, then tip into the pan with the onions.

Add the remaining butter to the frying pan and cook the mushrooms over high heat for 3–5 minutes until softened, then tip into the onion and chicken mix. Add the stock and mustard to the frying pan and bring to a boil, stirring well. Stir in the sour cream and taste for seasoning, adding salt and pepper if needed. Stir this mixture into the chicken in the saucepan and simmer gently for 5–10 minutes until the sauce is rich and thick.

Stir in the butter beans and parsley, heat through the beans, then season to taste with salt and pepper to serve.