- Using the green part of the blanched leek, line a mould.
- Place the ham into the stock and braise for four hours until the meat falls away from the bone.
- Remove the ham from the stock and flake the meat into a bowl. Add the mustard seeds and check the seasoning.
- Place the ham and mustard seed mixture into the leek-lined mould. Press down then add the carrots and leek randomly on top of the ham. Repeat the layers, pressing down firmly each time.
- Cover the mould with cling film and place in the fridge with weights on top. Leave to chill for 24 hours.
- For the piccalilli, place a splash of olive oil into a pan and cook the onion until soft. Add the cauliflower and the rest of the ingredients. Heat and cook until the vegetables are soft but leaving the cauliflower with a slight bite.
- Using a sharp knife, slice the ham terrine and serve with the piccalilli. Garnish with watercress.