Creamy Coleslaw: Combine sugar, pepper and celery seed. Stir in first-listed horseradish and yellow mustard. Add mayonnaise. Mix well. Stir in vinegar. Toss with cabbage, carrots and onions. Mix well. Keep refrigerated until ready to use.
Horseradish Mustard: Combine Dijon mustard and horseradish in a bowl. Mix well. Keep refrigerated until ready to use.
Sandwich Build: Place 2 slices provolone cheese on bottom of roll. Place about 3 ounces pastrami on top of cheese. Place ½ cup Creamy Coleslaw on top of pastrami. Spread 2 tablespoons Horseradish Mustard on crown of roll. Place crown of roll on sandwich and close. Cut in half and serve.