1. Preheat the oven to 400°F (200°C). Season the hens inside and out with salt and pepper.

2. Heat the butter with 1 tbsp of the oil in a large, deep, flameproof casserole over medium heat. Add the hens and cook, turning occasionally, for about 10 minutes, until browned. Transfer the hens to a platter.

3. Add the remaining 1 tbsp oil to the casserole. Add the bacon, onion, leek, and celery and cook, stirring often, for about 3 minutes, until lightly colored. Add the walnuts. Return the hens to the casserole.

4. Tuck the cabbage wedges loosely into the pot and season with salt and pepper. Pour in the hot stock. Bring to a boil and cover. Bake for 40–45 minutes, or until the vegetables are tender and the guinea hen juices run clear with no sign of pink when pierced with the tip of a sharp knife.

5. Remove from the oven and let stand for 10 minutes. Transfer the hens to a carving board and cut each in half or into quarters. Place on dinner plates, top with the vegetables and pan juices, and serve hot.