Creole Mustard is a variation of wholegrain mustard where the seeds are slightly crushed. They are not ground nor are they whole. The ingredients in Creole Mustard can vary from producer to producer slightly, however, they all have the same basic flavor. However, some are better than others. Creole Mustard can substitute American style mustard in most any recipe. There are two basic styles of mustard: those that are smooth and those that contain whole or rough ground seeds of the mustard plant.