Gather all your ingredients on the countertop for a smooth and efficient process.
Using a grater, finely grate the yellow onion and include the juices.
In a mixing bowl, combine the grated onion, mayo, sweet pickle relish, yellow mustard, white vinegar, sweet paprika, onion powder, garlic powder, and salt.
Mix all the ingredients together with a whisk or fork until smooth and creamy.
Taste the sauce and adjust flavors as desired with more vinegar, mustard, or relish.
Cover the bowl and let the sauce chill in the refrigerator for at least 30 minutes.
