How to Make It
Preheat the oven to 450°. On a rimmed baking sheet, brush the chicken legs with olive oil and season with salt and pepper. Roast for 35 to 40 minutes, until browned and cooked through. Leave the oven on.
Meanwhile, in a large, deep ovenproof skillet, heat the 1 tablespoon of olive oil. Add the sausage and cook over moderately high heat, breaking up the meat with a wooden spoon, until nearly cooked through, about 8 minutes. Add the onion, fennel and carrot and cook, stirring occasionally, until the vegetables are softened, about 8 minutes. Add the garlic, rosemary, thyme and ground fennel and cook, stirring, until fragrant, about 3 minutes. Stir in the stock and beans and bring to a boil.
Nestle the chicken legs in the stew and sprinkle the panko and cheese evenly on top. Bake the cassoulet in the upper third of the oven for 20 to 25 minutes, until bubbling and the topping is crisp. Let stand for 15 minutes before serving.