01 - Pat the chicken breasts dry with paper towels. If breasts are 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: fill the first with 1/2 cup all-purpose flour, whisk 2 large eggs with 2 tablespoons whole milk in the second, and combine 3/4 cup grated Romano cheese, 1/4 cup grated Parmesan cheese, and 1 cup Italian-style breadcrumbs in the third.
03 - Dredge each seasoned chicken breast through the flour, shaking off excess. Dip into the egg wash, allowing any extra to drip off. Press firmly into the cheese-breadcrumb mixture, coating both sides evenly and ensuring the crust adheres well.
04 - Heat 1 tablespoon unsalted butter and 2 tablespoons olive oil in a large skillet over medium-high heat. Place the breaded chicken in the pan and cook 4 to 5 minutes per side until deeply golden and cooked through to an internal temperature of 165°F. Work in batches if needed, adding more oil between batches. Transfer finished cutlets to a plate and tent loosely with foil to keep warm.
05 - Reduce the skillet heat to medium. Add the remaining 1 tablespoon butter and 1 tablespoon olive oil. Sauté 2 cloves minced garlic for 30 seconds until fragrant. Pour in 1 cup low-sodium chicken broth along with the zest and juice of 1 large lemon. Simmer for 3 minutes, using a spatula to scrape up the fond from the bottom of the pan.
06 - Return the chicken cutlets to the skillet and spoon the lemon sauce generously over each piece. Simmer together for 2 minutes so the flavors meld. Garnish with 2 tablespoons chopped fresh parsley and lemon slices. Serve immediately.