Turn heat down to medium and add wine to deglaze the pan, scraping up the bottom of the pan. Add garlic then cook, stirring, until liquid is almost gone about 2 minutes. Stir in broth, lemon juice and capers. Return chicken to the pan and cook on each side until chicken is cooked through about 3 minutes a side. Transfer cutlets to a warm plate.
Off heat whisk butter into the sauce. Pour sauce over chicken and top with parsley and lemon slices if using.