The key to this beautiful French-style dish is roasting the chicken directly on the bars of the oven, so the chicken juices rain down on the potatoes as they cook.
1 whole free-range chicken with giblets (1.7 kg)
1.2 kilograms Charlotte potatoes
100 grams salted butter
2 bulbs of garlic
3 small onions
1 teaspoon olive oil
1/2 bunch of fresh rosemary (15 g)
400 grams green beans
1 teaspoon Dijon mustard
1 tablespoon walnut oil
1 tablespoon extra virgin olive oil
White wine vinegar
1/4 clove of garlic
25 grams shelled walnuts
Preheat the oven to 400ºF (200°C) and get your oven racks into position – one in the middle and one just above.
Slice the potatoes in half lengthways and slice the tops off the garlic bulbs, then place in a shallow roasting tray. Season generously with sea salt and black pepper and drizzle with one teaspoon of olive oil, then set aside.
Remove the giblets from the chicken. Using a large sharp knife, carefully cut down the back of the chicken and open it out flat. Rub the butter and a good pinch of salt and pepper all over both sides.
Place the potato tray on the bottom shelf of the oven, and the chicken directly onto the shelf above. Place the unpeeled onions on top of the chicken and roast for an hour and 10 minutes, turning the potatoes regularly and brushing the chicken with the cooking juices using the rosemary sprigs.
Trim the beans and cook in boiling salted water for five minutes, or until tender. Finely chop the walnuts.
Spoon the mustard into a bowl, peel and finely grate in the garlic, then whisk in 1 tablespoon each of extra virgin olive oil and walnut oil. Season to perfection with salt and pepper.
Drain the beans and toss them in the dressing, then tip onto a serving plate and sprinkle with the walnuts.
Remove the chicken from the oven and leave to rest for a few minutes. Squash the onions and garlic out of their skins and toss through the potatoes. Serve with the chicken and green beans.