Skate, Leek and Watercress Terrine

• 12 thin leeks, or 3 larger ones, trimmed and rinsed
• large bunch of watercress, leaves only

Use the white part of the leeks, and split the larger ones lengthways into 4. Poach in water for 15 minutes or so until tender. Remove from the water and drain on paper towels.

Meanwhile, blanch the watercress. Season the skate, put into the vegetable cooking water, bring to just simmering point, put the lid on, and cook the fish for 5 to 8 minutes. Remove it from the heat. When cool en