1 Cup walnut pieces
2 Cups cilantro leaves, washed, drained and stemmed
1 Green jalapeno pepper, seeded and chopped (optional)
1 Teaspoon salt, or to taste
2 Tablespoons cider vinegar
Put the walnuts in a food processor and grind them fine.
Add the cilantro, jalapeno peppers, salt, vinegar and 2 to 3 tablespoons of water to blend. Blend in a little more water if necessary to make a thick sauce. Taste and correct the seasoning, adding more salt if necessary.