Trim the ends from the leeks and cut them into quarters length-ways, wash them and keep them in water.
Peel the carrot, parsnip and turnips, top and tail them and then peel again into long strips.
Pick the leaves from the herbs. Pick the large stalks from the watercress and discard.
Heat a wok or large frying pan, add the walnuts and cook for 2 minutes, remove them and then add the butter and oil, when warm add the vegetables and cook for 3 or 4 minutes to soften the veg, be careful not to over cook them. Drain the vegetables, toss with the herbs and the walnuts.
For the dressing: Heat the jam in a small saucepan or a microwave, when liquid put in a bowl and whisk in the vinegar and oil.
Season the slaw with salt and pepper and dress with the vinaigrette.
«Use different vegetables for the season, celery and courgette are great in summer and sliced cep mushroom and celeriac works well in winter. »