Pour the bag of coleslaw mix into a large bowl with a fitted lid.
Season the slaw mix liberally with salt, black pepper, and cayenne pepper.
Stir all of the remaining ingredients until well combined in another bowl with a fitted lid.
Cover and refrigerate both bowls separately in the fridge for at least 30 minutes, but up to several hours.
Stir the coleslaw dressing into the seasoned slaw mix.
Let stand out at room temperature 15 minutes, then give it a really good stir before serving. Initially, the vinegar will be a bit overpowering. However, letting the Cajun coleslaw stand out for several minutes makes the flavors balance out quickly.
You can use any coarse mustard in place of the Creole mustard if needed.You can also sub white or apple cider vinegar for the Steens' cane vinegar. If you do, increase the sugar to 1 ½ teaspoons. For best results, use cold mayonnaise and gluten free ranch dressing.