Slice the bread into manageable sections, then carefully cut each into halves lengthwise to reveal a hollowed interior.
Brush the cut sides of the bread with olive oil to help keep it moist and add flavor; set aside.
Spread a layer of mayonnaise or aioli on the inside of each bread half for added creaminess and tang.
Layer slices of cured meats — mortadella, salami, and prosciutto — inside the bread, arranging them evenly for a colorful, layered look.
Add sliced cherry tomatoes and pickled banana peppers on top of the meats for a burst of acidity and brightness.
Sprinkle shredded mozzarella evenly over the filled bread, covering the ingredients for a cheesy, melty finish.
Close the sandwich halves gently, pressing down slightly to compact the fillings and help hold everything together.
Wrap the assembled sandwiches in foil or place them on a baking sheet, then bake in a preheated oven at 375°F (190°C) for about 10 minutes until the cheese melts and the bread is toasted golden.
Remove from the oven and let rest for a minute; then unwrap or slice into smaller portions if desired.
Slice the sandwich into halves or quarters, revealing the colorful layers of meats, vegetables, and melted cheese, ready to enjoy.
Serve warm, with extra condiments or pickled peppers on the side for added flavor.