- 1 cucumber, peeled, seeded, and diced fine (about 3/4 cup)
- 3/4 cup sour cream
- 3 tablespoons drained bottled horseradish, or to taste
- 1 teaspoon white-wine vinegar, or to taste
- 2 teaspoons minced fresh tarragon leaves, or to taste, plus a tarragon sprig for garnish
- In a bowl whisk together the cucumber, the sour cream, the horseradish, the vinegar, the minced tarragon, and salt and pepper to taste and chill the sauce, covered, for at least 2 hours and up to 1 day. Transfer the sauce to a serving dish and garnish it with the tarragon sprig.