01 - Place chicken breasts between two sheets of plastic wrap and pound to an even ½-inch thickness using a meat mallet. Season both sides generously with salt and freshly ground black pepper.
02 - Arrange three shallow dishes: the first with all-purpose flour, the second with beaten eggs whisked together with 2 tablespoons of water, and the third with Romano cheese thoroughly combined with breadcrumbs.
03 - Dredge each seasoned chicken breast in flour, shaking off any excess. Dip into the egg wash, allowing the surplus to drip off, then press firmly into the Romano-cheese breadcrumb mixture, ensuring an even and adherent coating on all sides.
04 - Heat olive oil and 2 tablespoons of unsalted butter in a large skillet over medium heat. Working in batches if needed, add the breaded cutlets and cook for 3 to 4 minutes per side until deeply golden and cooked through to an internal temperature of 165°F. Transfer to a warm plate and tent loosely with aluminum foil.
05 - Pour off any excess oil from the skillet. Add the fresh lemon juice and lemon zest to deglaze the pan, scraping up all caramelized bits from the bottom. Stir in the remaining 2 tablespoons of butter and simmer gently for 1 to 2 minutes until the sauce slightly thickens and becomes glossy.
06 - Return the chicken cutlets to the skillet and spoon the lemon-butter sauce generously over each piece. Cook for 1 to 2 minutes to reheat through and allow the flavors to meld.
07 - Transfer to serving plates, sprinkle with chopped fresh parsley, and garnish with lemon slices if desired. Serve immediately.