Chilled Cucumber-Buttermilk Soup

1-1/2 ­lb. cucumbers, peeled, seeded, and cut into chunks
2 medium celery stalks, roughly chopped
1 small shallot, coarsely chopped
1/4­ cup extra-virgin olive oil, more to garnish
Kosher salt
1/2 cup sour cream
1/2 ­cup buttermilk
Freshly ground black pepper
Chopped chives, to garnish
In a blender, purée the cucumber, celery, shallots, olive oil, and 1 tsp. kosher salt until smooth. Strain through a medium-mesh sieve into a large bowl, pressing on the solids to extract as much liquid as possible. Whisk in the sour cream and buttermilk and season to taste with kosher salt and freshly ground black pepper. Refrigerate until chilled, at least 1 hour. Serve drizzled with olive oil and garnished with chives.

Make Ahead Tips
You can make this soup up to 2 days ahead.

nutrition information (per serving):
Calories (kcal): 200; Fat (g): fat g 19; Fat Calories (kcal): 170; Saturated Fat (g): sat fat g 5; Protein (g): protein g 2; Monounsaturated Fat (g): 11; Carbohydrates (g): carbs g 6; Polyunsaturated Fat (g): 1.5; Sodium (mg): sodium mg 490; Cholesterol (mg): cholesterol mg 15; Fiber (g): fiber g 1;