Herbed Mayonnaise
["1/4 lb. spinach leaves", "2 Tbsp. chopped onion", "1/4 c. watercress leaves", "1/4 c. chopped parsley", "1 Tbsp. tarragon", "2 1/2 c. mayonnaise"]
["Put all ingredients, except mayonnaise, in a small saucepan and cover with boiling water.", "Cook 1 minute.", "Drain and rinse under cold running water.", "Finely chop the mixture, or process quickly in a food processor.", "Stir in mayonnaise.", "Refrigerate until ready to use."]
["spinach leaves", "onion", "watercress leaves", "parsley", "tarragon", "mayonnaise"]