Lay the chicken breasts out on a cutting board and season them generously on both sides with salt and pepper. Set aside.
Next it’s time to set up your breading station. Set out three bowls, and in the first bowl add the zested parmesan cheese, then the eggs in the second bowl, and the panko bread crumbs in the third. Strip the leaves from the fresh rosemary sprig and mince them finely with a knife. Add the minced rosemary to the egg bowl, then whisk the eggs and rosemary together until combined.
Heat up a large skillet over medium heat, and let it heat up while you bread the chicken.
First dip each chicken cutlet into the parmesan, shake off the excess, then dip into the egg, then let the excess drip off, then finally dip into the panko bread crumbs (by the way, the reason we shake off the excess during each step is to prevent our breading from falling off later).
When the pan is nice and hot, add enough olive oil to coat the bottom of the pan, about 2-3 tbsp. Add 2 or 3 chicken cutlets to the hot oil (do not crowd the chicken cutlets), and cook for 4-5 minutes on each side, until golden and crispy. If the bread crumbs are browning too quickly, you can turn the heat down. Repeat with the remaining cutlets, and enjoy!