Ingredients
1 cup mayonnaise
1 cup fresh flat-leaf parsley leaves
1 scallion, roughly chopped
1 tablespoon fresh tarragon leaves
1 teaspoon white-wine vinegar
2 anchovy fillets, or 1 1/2 teaspoons anchovy paste (optional)
1 garlic clove, coarsely chopped
Preparation
In a food processor, combine all of the ingredients. Process until smooth and creamy.