Take chicken breast over a sheet of plastic wrap. Slit it open but not all the way through. Open it like a book. Place another sheet of plastic wrap over it. Bash it with a rolling pin so it is in even thickness.
Take flour, salt and pepper in a bowl. Set aside.
Take egg, parsley, salt and pepper in a bowl and mix well. Set aside.
Take chicken, coat in flour and then coat in egg and place it over a pan which has some butter. Cook for 5 mins on each side.
Remove it and set aside.
IN the same pan, add garlic, white wine or chicken stock. Add salt, pepper and lemon juice. Now add some butter and mix well.
Place chicken back in and cook for 2 to 3 mins on each side.
Remove to a plate. Reduce the sauce and pour over chicken. Serve.