Preheat your oven to 350°F (175°C).
Slice the Italian bread horizontally and place the bottom half in a greased baking dish.
Layer the salami, ham, provolone, and pepperoni evenly over the bread.
Add the shredded lettuce, tomato slices, red onion, and banana peppers.
Drizzle Italian dressing evenly over the toppings.
Finish with the top half of the bread, drizzling with olive oil, oregano, and garlic powder.
Cover with foil and bake for 20 minutes. Remove foil and bake for an additional 10 minutes.
Remove from oven and let cool for 5–10 minutes before slicing into squares.