Active Time

　　15 min

　　Total Time

　　15 min

　　Shot through with tarragon, parsley, and scallions, this tangy sauce pairs beautifully with rich southern-fried sweetbreads . If you have any left over, use it as a salad dressing or as a dip for crudités.

Ingredients

　　1/2 cup mayonnaise

　　1/3 cup well-shaken buttermilk

　　2 tablespoons white-wine vinegar

　　1/4 cup coarsely chopped flat-leaf parsley

　　2 scallions, white and pale green parts chopped and greens finely chopped (reserve separately)

　　1 teaspoon anchovy paste

　　2 tablespoons finely chopped tarragon

　　Pulse mayonnaise, buttermilk, vinegar, parsley, white and pale green parts of scallion, anchovy paste, and 1/4 teaspoon each of salt and pepper in a food processor until parsley and scallion are finely chopped. Transfer to a bowl and stir in scallion greens and tarragon. Chill until ready to use.

　　Cooks’ note:

　　Sauce can be chilled up to 1 day.