Using coconut milk as a base makes this soup is rich and creamy without a drop of cream. Slideshow: More Latin American Recipes
In a medium heavy pot, heat the oil over medium high heat, then stir in the onions and garlic along with 3/4 teaspoon each of salt and pepper, and cook until golden, about 6 minutes. Stir in the cilantro stems, stock, beans with their liquid and coconut milk and bring to a simmer. Simmer the soup until the cilantro stems are tender, about 5 minutes.
Puree the soup in batches, then season with salt and pepper to taste and serve topped with the cilantro leaves.