Start by slicing each chicken breast horizontally to make two thinner cutlets. This ensures even cooking and helps the chicken cook much faster without drying out.
Coat the cutlets evenly with lemon pepper seasoning and a little salt. Then lightly dredge both sides in flour, shaking off excess. Set them aside while the pan heats up so the coating sticks well.
Heat butter and oil in your skillet over medium heat. Place the cutlets in a single layer and cook for about 3 minutes per side until golden and almost cooked through, then transfer them to a plate.
Add more butter to the skillet and sauté garlic briefly until fragrant. Pour in chicken stock and fresh lemon juice, then let it simmer and reduce slightly. Taste and adjust seasoning if needed.
Bring the chicken back into the pan and spoon the sauce over the top. Remove from heat and let the chicken soak up the flavors. Finish with parsley and optional lemon slices for serving.