Push the avocados through a fine sieve. Place the avocado puree in a mixing bowl. Add the lime juice. Gradually add the chicken stock, stirring constantly.
When the avocado has been thoroughly blended with the broth, slowly add the crema. The mixture should be smooth and creamy. Season with salt and pepper.
Chill the soup until cold and serve in chilled bowls. Pass the Salsa Fresca to use as garnish.
Whisk the cream and the buttermilk together in a bowl. Cover and set in a warm place (a gas oven with just the heat from the pilot light is fine) for 8 hours. Crema may be kept in the refrigerator for as long as a week.
Combine all of the ingredients in a mixing bowl. Stir and toss well. Store in a covered container in the refrigerator no more than 1 day.
c.1997, M.S. Milliken & S. Feniger, all rights reserved