Used to eat at the Authentic from day one. (A friend was one of his first waitresses when the joint only had 6 tables) While our Chowhound moderators may not approve of this string existing on THIS page, here's the recipe I use whenever I want to duplicate the cilantro pesto:
2 cups, packed CILANTRO, large stems removed
½ cup BLANCHED ALMONDS
¼ cup chopped RED ONION
½ tsp chopped and seeded SERRANO CHILE
½ tsp KOSHER SALT
¼ cup OLIVE OIL
In a food processor, pulse the cilantro, almonds, onion, chile, and salt until well blended. With the food processor running, slowly add the olive oil in a steady stream. Add more oil as needed for your use. Makes about 1 cup.