This sauce is another good use for the tougher watercress stems and less-than-perfect leaves.  If making up to 1 week ahead, cover and chill (it will thicken slightly).  Serve as a salad dressing or as a dip for cold, cooked shrimp, or drizzle over poached chicken breasts.

Makes:  About 1 1/2 cups

     4    ounces watercress
     1    cup mayonnaise
     2    tablespoons lemon juice
     2    teaspoons anchovy paste
     1    clove garlic, peeled
           salt and pepper

1. Rinse watercress and drain well; pat dry with towels, then coarsely chop.
2. In a blender or food processor, whirl watercress, 1/2 cup mayonnaise, lemon juice, anchovy paste, and garlic until smooth.
3. Pour into a bowl and whisk in remaining mayonnaise until smooth.  Add salt and pepper to taste.