How to Make It
In a medium saucepan, heat the 2 tablespoons of oil. Add the onion, fennel, garlic and a generous pinch each of salt and pepper and cook over moderately low heat until the vegetables are softened, 8 to 10 minutes. Transfer the vegetables to a blender and let cool.
Add the 1 pound of sour cherries, the buttermilk, sour cream, sugar and 1/2 cup of water to the blender and puree until smooth; season with salt and pepper. Transfer to a large bowl, cover and refrigerate until well chilled, at least 1 hour.
Ladle the soup into bowls and drizzle lightly with oil. Garnish with dill, parsley and a few cherries and serve.