Arrange three shallow bowls: one with flour combined with garlic powder, onion powder, and Italian seasoning; one with beaten eggs; and one with Italian breadcrumbs. Line a sheet tray with parchment paper and place a wire rack nearby for resting the breaded cutlets.

Season both sides of each pounded flank steak cutlet with salt and pepper. Working one piece at a time, dredge each cutlet first in the seasoned flour, then dip it in the beaten eggs, and finally coat it thoroughly in the breadcrumbs. Place the breaded steaks on the prepared wire rack.

In a large skillet, heat approximately 1 inch of avocado oil over medium heat. Once hot, carefully add two steaks to the skillet and pan fry for about 2 minutes per side, or until golden brown. Adjust the heat as needed to prevent burning. Transfer the cooked steaks to the parchment-lined tray. Repeat the frying process with the remaining cutlets.

In a saucepan over medium heat, warm the marinara sauce until it is hot and gently simmering.

Submerge each fried steak in the hot marinara sauce, then transfer the steak to a sandwich roll. Top generously with shredded mozzarella cheese.

Place the assembled sandwiches on a baking tray and broil briefly until the cheese is melted and bubbly, watching closely to prevent burning.

Wrap each sandwich in aluminum foil and allow it to rest for 3 to 5 minutes. This brief steaming process softens the bread and melds the flavors. Serve immediately.