1. Heat the barbecue with the lid to 200°C (392°F).
2. Rinse the fennel and cut off the stems. Reserve some of the greens for garnish.
3. Pat dry the fennel and place it in an aluminum tray.
4. Cover with coarse sea salt and place it in the middle of the grill. Close the lid and cook for 15 to 20 minutes.
5. Remove from the barbecue and let it cool.
6. Cook the orange juice with the zest until it reduces by half.
7. Let it cool and mix it with olive oil. Season with pepper and salt.
8. Cut the Berloumi into slices of ½ cm thickness.
9. Cut the grapes in half.
10. Arrange the watercress on a plate.
11. Break the salt crust around the fennel and release the vegetable. Cut it into slices and arrange them on the salad. Add the grapes.
12. Grill the Berloumi for a few minutes on each side on the hot grill and place it on top of the vegetables.
13. Drizzle with the orange sauce, season with pepper, and garnish with fennel fronds.