Preheat the oven to 200°C (390°F). Place the butter, tarragon, lemon rind, salt and pepper in a small bowl and mix to combine. Place the butter under the skin of the chicken. Heat a large non-stick frying pan over high heat. Cook the chicken skin-side down for 4 minutes or until crispy, turn and cook for a further 2 minutes. Place the beans and lemon thyme in a baking dish and pour over the stock. Top with the chicken, pour over the butter from the pan and bake for 12−15 minutes or until the chicken is cooked through and the beans are tender. Serves 4.