Set up three shallow bowls: one with flour seasoned with a pinch of salt, one with beaten eggs, and one with a mixture of panko breadcrumbs, grated Parmesan, Italian seasoning, garlic powder, and a pinch more salt. This is your breading station.
Pat the chicken cutlets dry. Dredge each piece first in flour, tapping off excess, then dip in egg, and finally press into the crumb mixture, turning to coat all sides. Place the breaded chicken on a rack while you prepare the pan.
Preheat a large skillet over medium heat and add about 2 tablespoons of olive oil. When the oil shimmers, add the breaded chicken, cooking in batches if needed. Fry until golden and cooked through, about 3–4 minutes per side. Transfer to a sheet pan lined with parchment.
Preheat the oven to 400°F (200°C). Spoon a thin layer of marinara onto each piece of garlic bread, just enough to moisten the surface but not soak it. Place the bread halves on a baking sheet, cut side up.
Top each chicken cutlet with a generous spoonful of marinara, then sprinkle with shredded mozzarella. If you like a little extra cheese, add a second light sprinkle on top.
Bake the assembled sandwiches for 10–12 minutes, or until the mozzarella is fully melted and the bread is toasty around the edges. If you want extra crispiness, broil for the last 1–2 minutes, watching closely so it doesn’t burn.
Remove from the oven, let rest for 2 minutes, and garnish with chopped basil or parsley if using. Serve immediately while hot and gooey.