You can slice the chicken breasts horizontally into thin pieces or pound them with a mallet.
Heat the oil and butter over medium heat in a large skillet while you dredge the chicken pieces in flour, then salt and pepper them.
Cook the chicken 3-4 minutes per side until cooked through.
Remove the chicken from the pan and add the garlic, cooking and stirring a minute or so until softened.
Add the wine and/or broth and cook a few minutes until the sauce is thickened, then add the lemon juice and capers and heat through.
Return the chicken to the pan and warm up. Sprinkle with the fresh parsley.