Bring a large pot of water to a boil. Add the spinach and cook for 2 minutes, until soft. Fish the spinach out of the pot and place it in a large collander. Put it under cold running water until cool enough to handle. Squeeze the spinach with your hands to remove excess liquid. Place it in a bowl lined with a paper towel.
Meanwhile, in a food possessor, pulse the cilantro, parsley, walnuts, and garlic until finely chopped. Add the spinach and process for about 30 to 60 seconds, or until smooth.
Season to taste with the vinegar and spices.
Serve the pkhali right away or refrigerate until needed. Georgians say it’s always better the next day!