2 cups Cilantro
1 Jalapeno pepper
1 tsp Salt
2 tbsp Cider vinegar
Put the walnuts in a food processor and grind until fine.
Add the cilantro, jalapeño pepper, salt, vinegar and 2 to 3 tbsp of water and blend.
Blend in a little more water if necessary to make a thick sauce.
Taste and correct the seasoning, adding more salt if necessary.