01 - Pat the chicken breasts dry with paper towels. If thick, place between two sheets of plastic wrap and pound to an even 1/2-inch thickness using a meat mallet. Season both sides generously with salt and black pepper.
02 - Arrange three shallow dishes: the first with all-purpose flour, the second with beaten eggs and milk whisked together, and the third with a combined mixture of Romano cheese, Parmesan cheese, and Italian breadcrumbs.
03 - Dredge each seasoned chicken breast through the flour, shaking off excess. Dip into the egg wash, then press firmly into the cheese-breadcrumb mixture, ensuring an even, adhered coating on all sides.
04 - Heat 1 tablespoon butter and 2 tablespoons olive oil in a large skillet over medium-high heat. Add the breaded chicken and cook 4 to 5 minutes per side until golden brown and cooked through to an internal temperature of 165°F. Work in batches if needed, adding more oil as necessary. Transfer to a plate and cover loosely to keep warm.
05 - Reduce the heat to medium. In the same skillet, add the remaining 1 tablespoon butter and 1 tablespoon olive oil. Sauté the minced garlic for 30 seconds until fragrant. Pour in the chicken broth, lemon zest, and lemon juice. Simmer for 3 minutes, scraping up any browned bits from the bottom of the pan with a spatula.
06 - Return the chicken to the skillet and spoon the lemon sauce over the cutlets. Simmer together for 2 minutes, allowing the flavors to meld and the sauce to slightly reduce.
07 - Transfer to a serving platter, spoon remaining sauce over the chicken, and garnish with chopped fresh parsley and lemon slices. Serve immediately.