Add 16 ounces mayonnaise, 2 tablespoons tomato paste, 2 tablespoons butter, 1 tablespoons garlic powder, 2 teaspoons onion powder, 1 tablespoon smoked paprika, 1/4 cup water, and 3 tablespoons granulated sugar to a medium bowl or a small food processor. Stir or blend to combine.
Check the flavor and consistency. For a spicy yum yum sauce, add hot sauce, cayenne pepper, or red pepper flakes to taste. For a sweeter sauce, add 1/4 teaspoon sugar at a time. For a thinner sauce, stir in additional water 1 tablespoon at a time. Mix once more.
Use immediately or pour the yum yum sauce into an airtight container and let it sit overnight in the fridge for best results.
Notes
Tomato paste vs. ketchup: You can substitute 2 tablespoons of ketchup for the tomato paste. Since ketchup is already sweetened, start with 1 tablespoon of sugar and add more to taste.
Make it spicy: Stir in 1 teaspoon hot sauce, 1/4 teaspoon cayenne pepper, or 1/2 teaspoon crushed red pepper flakes for a spicy yum yum sauce.
For best flavor: While you can serve the sauce right away, letting it chill for at least 30 minutes (or overnight) allows the flavors to meld.
Storage: Store in an airtight container in the refrigerator for up to 1 week.