1. Preheat the oven to 140 °C (5).
2. Wash and peel the vegetables and cook them separately in boiling water with a pinch of salt, no more than 2-3 minutes for the carrots and 5 minutes for the turnips and fennels.
3. Transfer the vegetables to 4 mini round casseroles with the butter and season to taste. Add the chopped chervil and chives, then the duck slices.
4. Cook for about 15 minutes. Cover and serve.