Chilled cucumber and buttermilk soup is a rite of fancified summer lunches. Packed full of herb-y greenness and the refreshing coolness of cucumber, there’s also a hint of serrano chile, just enough to give you a kick and command your attention.
Put the cucumber, scallions, serrano, herbs, and water in a blender and puree until smooth. Pour into a large bowl and stir in the buttermilk, lemon juice, and salt. Taste and add more lemon juice or salt if desired.
Serve immediately or cover and refrigerate until serving. Ladle into bowls. Top with a drizzle of olive oil, a pinch of sliced mint, and a few grates of lemon zest.
Use a salad spinner to quickly clean and dry herbs. Measure the herbs, then place them together in the basket of a salad spinner. Rinse under cold running water and spin dry.