20-24 trimmed young leeks, well washed
200ml/7fl oz verjuice or sweet white wine
300ml/10fl oz water
8 whole black peppercorns
4 thyme sprigs
3 bay leaves
For the vinaigrette
11/2 tsp Dijon mustard
1 tbsp single cream
Sea salt and black pepper
11/2 tbsp red-wine vinegar
80ml/3fl oz extra-virgin olive oil
2 eggs, hard-boiled
1 tbsp capers, preserved in salt and well rinsed in tepid water
A handful of black olives (ideally Niçoise or Ligurian)
Small bunch of curly parsley, stalks removed and finely chopped
Check that the leeks are thoroughly clean. Pour the verjuice and water into a pan (large enough to hold all the leeks) and add the peppercorns, thyme and bay leaves. Place over a medium heat and bring to a gentle boil, then add the leeks. Turn down the heat slightly and simmer gently for 8-10 minutes, or until tender.
Next, make the dressing. Put the mustard and cream into a small bowl, add a little salt and pepper and whisk together. Add the wine vinegar and stir to combine. Now, slowly add the olive oil in a thin, steady stream, whisking constantly to emulsify. Set aside for five minutes, to allow the flavours to get to know each other.
Meanwhile, peel the hard-boiled eggs and grate on the finest holes of your grater – they should have a very light texture. As soon as the leeks are cooked, remove from the pan and drain on kitchen paper. Lay neatly on top of each other on warm plates and spoon over half of the vinaigrette. Scatter the grated eggs, capers and olives randomly on top. Drizzle over the last of the vinaigrette, dust with pepper and sprinkle with chopped parsley to serve.