Preheat the oven to 425°F. Line a sheet pan with parchment paper if desired.
First we will marinate the salad. Together in a bowl, combine the chopped iceberg lettuce, along with the mayo, parmesan, vinegar, peppers, garlic, and seasonings. Mix until thoroughly combined. Set aside as the flavors soak into one another.
Next, slice the bread horizontally. Sprinkle ¼ cup of parmesan cheese to each side of the bread (totaling ½ cup). Then to one half of the bread (keep on side face open with only parm), add the turkey/chicken breast and cured meats in an even layer.
Top the meats with the provolone cheese and then pop the giant sandwich into the oven for 10 minutes. Once the cheese is melted and the bread looks golden brown, take the sandwich out of the oven.
Let the sandwich cool down for about 5 minutes, then stuff as much salad as you can fit into the sub. Top with the parmesan only side of the sandwich. It may be messy and drippy, but that's part of the experience.
Once the sandwich is stuffed with the lettuce mixture, slice it into 4 pieces. The portion sizes are pretty generous, so if this was a gathering I might split it into 8 pieces. Whatever works for you!
Devour this sandwich immediately. If you are making this just for yourself, do not add the salad mixture to the entire sandwich. It will get soggy if you save it as leftovers! Keep the lettuce mix separate if you are planning to not eat the whole thing!