In a first plate, mix the Panko breadcrumbs with the freshly grated Pecorino Romano.
Put the flour in a second plate and mix it with salt and black pepper. To a third plate, add the egg and beat it with a fork.
Dip your chicken breasts in flour first, then in the beaten egg and at last in the breadcrumbs.
Put the neutral oil in a frying pan and turn on medium-high heat. Once it's hot, add the chicken breasts and let them cook for 5 minutes on both sides, until it's perfectly golden.
Serve on plates with your side dish and sprinkle with fresh parsley.
Notes
Make ahead - I really recommend making this dish last minute, as it will be so much better.
Store - once it's totally cold, you can keep it in an airtight container for 2 to 3 days.
Reheat - use a frying pan with 1 teaspoon of neutral oil to reheat it. You can also put it in the oven on a baking tray lined with parchment paper at 160°C / 320°F for about 10 minutes.