1. Combine first 9 ingredients in a stock pot. Bring to a boil, reduce heat, and simmer, covered for 15 min.
2. Transfer the mixture into a food processor and blend until very smooth. Return the mixture to the stock pot. Add milk, buttermilk and lime juice. Heat soup to serving temperature.
Garnish individual bowls with cilantro.
Nutritional information does not include suggested side dishes.