Trim chicken breasts and slice in half length-wise so you end up with 4 equal-thickness cutlets.* Season with salt and pepper.
In a shallow bowl, stir together 1/2 cup flour, 1 tsp salt, and 1/2 tsp black pepper. In a second bowl, whisk 2 eggs until frothy. In a third bowl, stir together 1/2 cup Italian bread crumbs with 1/2 cup parmesan cheese.
Dip both sides of each chicken cutlet into the flour, tapping off excess, then dip in beaten eggs, letting excess egg drip off and finally dip into the cheesy breadcrumbs, pressing cutlets into breading to ensure a thick, even coating of crumbs.
Heat a large non-stick pan over medium heat and add enough olive oil to lightly coat the bottom of the pan. Once oil is hot, add chicken in batches (don't crowd the pan), sautéing 3-4 min per side or until golden brown and just cooked through.
Pour 1 1/2 cups of marinara into a 9x13 casserole baking dish. Arrange chicken over sauce in a single layer. Top each chicken down the center with remaining 1 1/2 cups marinara, then cover with shredded mozzarella. Bake uncovered at 425˚F for 15 minutes or until cheese is melted and sauce is bubbling. Garnish with chopped parsley or basil if desired.