Wash and dry the courgettes; remove the seeds with a small spoon. Remove the leaves from the celery; peel the carrots.

1. Cut the vegetables into little sticks and put them in the steam-cooker.
2. Cook them separately until they are tender, but not too soft.
3. Roll the sole fillets on the work surface while stuffing them with vegetables. Secure each one with a wooden skewer. Set the remaining vegetable strips aside for later use. Arrange the rolled fillets in the oven dish. Pre-heat the oven to 180°.
4. Finely chop the peeled shallots.
5. Transfer them to a saucepan along with the port, then reduce almost to dryness.
6. Add the vinegar and the sugar.
7. Put the rolled fillets in the oven for 10 minutes (oven at 180°C).
8. At the oven door, tilt the plate to collect the cooking juices. Set them aside for later use.
9. Bring the cooking to an end. Keep the rolled fillets warm on a plate under some aluminium foil (oven switched off).
10. Add the cooking juices to the vinegar sauce base and let it reduce to about the volume of a generous wine glass.
11. Off the heat, blend in the 100g of butter, a little at a time, stirring to bind the sauce together well. Check seasoning (salt & pepper).
12. Quickly heat the remaining vegetables with the 20g of butter.
13. Present in a warmed serving dish. Arrange the rolled fillets with the vegetables surrounding them, cover in sauce and serve immediately.