Whisk together the mayonnaise, pickle juice, yellow mustard, and ketchup until well combined.
Mix in the dry ingredients until the sugar and spices are dissolved.
Finally, stir in the pickles or relish and onions and mix until everything is well encorporated.
Store the sauce in an airtight container or jar and chill for at least 6 hours or overnight to allow the flavors to develop.
Combine mayonnaise, mustard, vinegar, and spices. Stir in the relish once everything else is well combined. Refrigerate and let sit for at least 30 minutes.
