Prepare Smoker: Preheat your smoker to 275 degrees Fahrenheit using fruit wood or oak. Smoke indirect.
Season: Start by scoring the mortadella along the length and width of the loaf. As the mortadella smokes the scoring allows more smoke to flavor it. Apply the mustard as a binder and liberally apply the dry rub.
Smoke: Place mortadella in the smoker and smoke for three hours. At the 2 hour and 45 minute mark, place the red wine sauce in a small bowl. Apply the glaze to the entire loaf and continue to smoke for 15 more minutes. The sauce will tack up.
Serve: Let the mortadella rest for 15 minutes. Thinly slice for sandwiches, a charcuterie board, or just to snack on.