Preheat the oven to 200°C (400°F).
Place the chicken pieces and potatoes in a large, deep-sided roasting pan. Add the lemon slices if using.
Whisk together the wine or verjuice, chicken stock, Dijon mustard, garlic and fresh herbs. Pour over the chicken and potatoes. Drizzle over the olive oil and season well with salt and pepper.
Roast uncovered for 1 hour, or until the chicken is cooked through and the skin is golden. The juices should run clear when the thickest part of the thigh is pierced with a sharp knife.
Serve with the pan juices spooned over, and a simple green vegetable or salad alongside.