Add all ingredients to a medium bowl and whisk until smooth and fully combined. Transfer to an airtight container.
Refrigerate for at least 5 hours before serving. For the best flavor, let it sit overnight. Stir before serving and enjoy!
Notes
Use good-quality ingredients for the best flavor; since this sauce is so simple, the mayo, ketchup, and seasonings really stand out.Storage: Store in an airtight container in the fridge for up to 4 to 5 days. Stir before serving.