1.
Chop the watercress and the leek and blanch them for one minute in a pot of boiling salted water.
2.
Transfer them to a colander and rinse in cold water. Place them in a blender with the butter (melted) and the
walnut milk and blend.
3.
In the same pot, cook the peeled and diced potatoes until tender.
4.
Mash the potatoes with a fork or a potato masher, add the watercress and leek purée and mix well until all the ingredients are incorporated. Add the
extra virgin olive oil, salt and pepper.
5.
Sprinkle with crushed walnuts.