Preheat your oven to 350°F.
Use a meat tenderizer to pound the chicken breasts to an even thickness. Season both sides with 1 teaspoon of salt and 1 teaspoon of pepper.
Heat a large skillet over medium heat and add 1 tablespoon of olive oil. Dredge each chicken breast in the flour, ensuring it is fully coated, then shake off any excess flour.
Place the chicken breasts in the pan, cooking for 3 to 4 minutes on one side. Flip them and cook for an additional 3 minutes. You may need to do this in batches. Once cooked, transfer the chicken to a baking dish and repeat with any remaining chicken, adding more olive oil if needed.
Once all the chicken is cooked, reduce the heat to medium-low and add the butter to the skillet. Stir in the garlic and cook for 30 seconds. Add the lemon slices and lemon juice, cooking for 2 to 3 minutes while flipping the lemon slices in the pan. Season with a pinch of salt and pepper. Pour the lemon-butter sauce over the chicken in the baking dish.
Bake for 15 to 20 minutes, or until the chicken reaches an internal temperature of 165°F. Remove from the oven and sprinkle with fresh parsley. Serve immediately.