Heat the oven to 200C/180C fan/gas 6. Heat the oil over a high heat in a large non-stick frying pan. Season the chicken thighs and fry, skin-side down, for 5 mins until golden and crisp. Transfer, skin-side up, to a large baking tray. (If you’re doubling up this recipe, fry in batches and divide between two baking trays.)

Fry the leeks in the pan for 5 mins or until just softened. Add the garlic and fry for 1 min more. Stir in the beans, then spoon into the tray, or trays, around the chicken. Pour the stock over the beans and season to taste. Roast for 20 mins, then remove from the oven and stir the mustard and crème fraîche through the beans. Roast for 10-15 mins more, or until the chicken is cooked through. To freeze, leave to cool completely and transfer to large freezerproof bags.

Scatter the lemon zest over the chicken and serve with crusty bread to mop up the juices.