- 2 large ripe but firm avocados
- 1 1/2 cups buttermilk
- 1 1/2 cups plain yogurt
- 2 heaping tablespoons chopped cilantro
- 1 large clove garlic, thinly sliced
- 1/2 serrano or jalapeño chile, seeds removed for less heat if desired, or more to taste
- 1/2 teaspoon toasted and ground cumin seeds
- 1 tablespoon freshly squeezed lime juice
- Kosher or sea salt
- 1 large plum (Roma) tomato, halved lengthwise, seeded, and cut into 1/4-inch dice
- 1/4 cup finely minced white onion
- 2 heaping tablespoons chopped cilantro
- 1/2 serrano or jalapeño chile, seeds removed for less heat if desired, finely minced
- 1 small clove garlic, finely minced
- Kosher or sea salt
- Freshly squeezed lime juice
- Halve and pit the avocados. Set aside half an avocado for the salsa. Put the remaining avocado flesh in a blender with the buttermilk, yogurt, cilantro, garlic, chile, and cumin. Blend until smooth. Taste and add more chile if desired, and then blend again. Transfer to a bowl and stir in enough cold water to thin the soup to a pleasing consistency, about 1/2 cup. Stir in the lime juice, or more to taste, and season with salt. Chill thoroughly.
- Just before serving, prepare the salsa: In a bowl, stir together the tomato, onion, cilantro, chile, and garlic. Cut the reserved avocado half into 1/4-inch dice and fold it in gently, and then season to taste with salt and lime juice and stir again gently to avoid mashing the avocado.
- If the soup has thickened in the refrigerator, whisk in ice water to thin it to the desired consistency. Taste for seasoning. Divide among 6 bowls. Top each serving with a spoonful of salsa and serve.