1 to 1 1/4 cups cooked mayonnaise
2 1/2 tablespoons finely chopped sweet pickle (about 1 large)
1 tablespoon snipped fresh parsley
1 1/2 tablespoons chopped onion OR 1 teaspoon instant minced onion
1 teaspoon prepared mustard

In medium bowl, stir together all ingredients until well combined. Cover and chill if not using immediately.