Preheat the oven to 200°C (180°C Fan) or 220°C/Gas 7.
Season the chicken with salt and pepper.
Brown the chicken in butter and olive oil, then remove and set aside.
Cook the onion until soft before adding the garlic.
Stir in the flour and cook for 1 minute.
Gradually add the chicken stock while stirring.
Mix in the honey, Dijon mustard, wholegrain mustard, Worcestershire sauce, tomato ketchup, lemon juice, paprika, and double cream.
Return the chicken to the pan and coat it with the sauce.
Transfer everything to a roasting dish with the potatoes.
Roast for 35–40 minutes, basting halfway through.
Rest for 5 minutes, garnish with parsley, and serve.