Preheat the oven to 180°C, fan 160°C, gas 4. Heat the oil in a large, heavy-based casserole dish and add the chicken. Fry for 5-10 minutes, turning halfway, until browned. Remove the chicken from the pan with a slotted spoon and set aside.
In the same pan, fry the shallots until just browned, then stir in the garlic, bacon, thyme and flour, and cook, stirring, for 2-3 minutes. Pour in the wine and chicken stock.
Return the chicken to the pan and bring to the boil, then reduce the heat. Cover and transfer to the oven for 1 hour, until the chicken is tender and cooked through. Add the mushrooms for the last 15 minutes of cooking.
Meanwhile, place the potatoes in a large saucepan of cold water and bring to the boil. Simmer for 12 minutes, until tender, then drain and mash with the milk and butter. Stir half the parsley through the coq au vin and season with salt and freshly ground black pepper. Sprinkle with the remaining parsley, then serve with the mash.
Cook’s tip: use red wine from Burgundy if you can – this bold, fruity red has been used in coq au vin by generations of French cooks.