- 3 medium leeks, trimmed
- 12 spring onions, trimmed
- 750ml/1 pint 6fl oz vegetable stock
- 1 bay leaf
- 3 leaves gelatine
- salt and freshly ground black pepper
- 2 tbsp roughly chopped fresh chervil
- 1 tsp English mustard
- 2 tsp white wine vinegar
- ½ lemon, juice only
- 250ml/9fl oz rapeseed oil
- salt and freshly ground black pepper
- 750g/1lb 10oz cooked ham, sliced, to serve
- For the terrine, place the leeks and spring onions into a wide shallow pan with the vegetable stock and bay leaf. Bring to the boil, then reduce the heat and simmer for 8-10 minutes, or until the vegetables are tender. Remove the vegetables from the pan and set aside.
- Return the pan to the heat and boil to reduce the volume of the stock by two thirds.
- Meanwhile, soak the gelatine leaves in cold water until softened. Strain, then add to the reduced stock. Whisk to combine, then strain into a bowl. Allow to cool, then season with salt and freshly ground black pepper and stir in the chervil.
- Place into the fridge and chill for 30 minutes, or until just setting, but still with a good wobble.
- On a work surface, place three large sheets of cling film one on top of the other. Lay the leeks in a row on the cling film, then top with the spring onions.
- Spoon over the jelly, then roll the cling film up into a large cigar shape, twisting firmly to enclose at both ends. Place in the fridge for at least an hour until fully set.
- For the dressing, whisk the mustard, vinegar and lemon juice together in a bowl. Slowly whisk in the rapeseed oil and season, to taste, with salt and freshly ground black pepper.
- To serve, slice the terrine into wedges and place onto serving plates with some slices of ham and a drizzle of dressing.