Whisk together the mayo, sour cream and milk until smooth. Add the spices and whisk until combined. Add the pickle relish and stir again.
Pour into a jar and chill in the refrigerator until ready to serve. This dressing will keep nicely in the refrigerator for up to a week.
Notes
¼ cup of prepared dill pickle relish may also be substituted for the minced pickles and pickle juice in this recipe. More relish may be added for increased pickle flavor.