Ingredients:

• 1 1/2 pounds green beans, trimmed
• 1/3 cup coarsely chopped fresh, flat-leaf parsley
• 1/4 cup mayonnaise
• 1/4 cup sour cream
• 1 1/2 cups sour cream
• 1 1/2 teaspoons red-wine vinegar
• 1/2 teaspoon fresh lemon juice
• 1/2 teaspoon anchovy paste
• 1/4 teaspoon salt
• 1/4 teaspoon black pepper

Preparation: Cook beans in a 6 to 8-quart pot of boiling, salted water, uncovered, until just tender (6 to 8 minutes). Drain in a colander and immediately transfer to a bowl of ice and cold water to stop cooking. When beans are cool, drain in a colander and pat dry.
Puree parsley, mayonnaise, sour cream, vinegar, lemon juice, anchovy paste, salt and pepper in a blender until smooth. Transfer to a bowl and toss with beans.

Notes: Sauce can be made 1 day ahead and chilled.