Combine the regular mustard, mustard powder, and cayenne pepper in a small bowl.
Mix these dry ingredients well for a balanced flavor.
Add the soy sauce, corn syrup, and white vinegar.
Stir the mixture until smooth, ensuring everything is well incorporated.
Whisk in the mayonnaise and sugar.
Make sure all the ingredients are blended for the perfect consistency.
Heat the mixture in the microwave for about 15 seconds.
This helps meld the flavors together.
Stir again to ensure everything is mixed well.
Allow the sauce to cool.
Refrigerate it for at least four hours to let the flavors develop.