• 1 cup walnut pieces
• 2 cups cilantro leaves, stems removed
• 1 jalapeno pepper, seeded and chopped
• 1/2 tsp salt, or to taste
• 1 Tbsp cider vinegar
• 1/2 cup purified water, or as needed

Grind the walnuts in a food processor until fine. Add the cilantro, pepper, salt, vinegar, and 2 to 3 tablespoons of water and blend. Blend in more water until the pesto is the consistency of a thick sauce. Taste and correct the seasoning, adding more salt if needed. Keep unused pesto refrigerated in a tightly covered container.

From "The Healthy Kitchen" (Knopf, 2002) by Andrew Weil, M.D., and Rosie Daley.