Sprinkle a bit of flour on a clean surface. Place the flank steak on it and flip it a couple of times to coat both sides with flour. Then, use a meat pounder to flatten it until it's less than 1/4 inch thick and nearly a foot square.
In a shallow dish, mix together the egg and water and place it nearby.
In another shallow dish, combine the bread crumbs, grated parmesan cheese, salt, and ground black pepper.
Heat cooking oil in a deep skillet to 360 degrees Fahrenheit.
Dip the flattened steak into the egg mixture, making sure it's fully coated, then dredge it in the seasoned bread crumbs and cheese mixture, ensuring it's evenly coated.
Carefully slide the coated steak into the hot oil and cook until it turns a light brown color, which takes about 4 minutes. Be careful not to overcook it.
Remove the cooked steak from the oil and place it on paper towels. Roll it up immediately so it will fit inside the bread.
Place the rolled steak inside the sliced Italian bread and top it with the shredded mozzarella cheese.
Pour warm marinara sauce over the steak and add giardiniera to your liking.
Don't be surprised if the sandwich looks a bit different from what you're used to. That's how a breaded steak sandwich is supposed to look!
Enjoy your delicious homemade Ricobene's Breaded Steak Sandwich!