Nice and easy and truly delicious:
You beat up an egg in a cup of milk in a bowl with some salt and pepper and you put your sliced chicken breasts in this liquid to soak for a few hours (to tenderize it).
You take the slices out and you dip them on both sides in flour till they are well covered.
You heat olive oil and butter in a frying pan and saute them on both sides till a golden brown ( 8 mins-10), not too fast!
Sprinkle with lemon and salt.