A well executed hoagie is all about a balance of fat and acid. The fat, in this case, is coming from a trifecta of deli meats (mortadella, capicola, and spicy soppressata) and parmigiano reggiano, and the acid from a combination of red wine vinegar and jarred giardiniera pickles. I like Marconi brand’s hot giardiniera best. If you’re spice averse, look for something labeled mild instead.