Slice each chicken breast lengthwise to make 4 thin cutlets. Work with your hand flat on top and keep the knife parallel to the cutting board so the pieces cook evenly instead of puffing thick in the center.

Stir the flour, lemon pepper seasoning, garlic powder, and salt together in a small bowl, then coat both sides of the chicken and press the mixture on gently. The surface should look lightly dusted rather than heavily breaded, which helps it brown instead of turning pasty.

Warm a large skillet over medium heat, add 2 Tbsp olive oil, then cook the chicken for 4 to 5 minutes per side until browned and the thickest part reaches 165 °F. You want a lively sizzle, a deep golden crust, and a cutlet that feels springy with slight resistance when pressed.

Turn off the heat, add the butter to the hot skillet, and scrape the browned bits from the pan as it melts, then stir in the lemon zest, lemon juice, lemon pepper seasoning, and parsley. The sauce should look glossy and lightly thickened, with tiny browned bits suspended in the butter instead of a greasy layer floating on top.

Return the chicken to the skillet and turn each piece in the sauce before spooning the extra over the top. Once coated, the cutlets should shine and smell bright, buttery, and peppery right before serving.