Oil for the pan, salt and pepper are ALWAYS freebies. So, please don't send me mail about the number of ingredients.
I like the bite of the vinegar in this dish. It gives it a little zing. If you don't like vinegar, leave it out. Also, it counts as an ingredient...
Same goes for parsley, I needed a punch of color and I had the parsley so I used it. If you don't have it, don't sweat it, but it does add a nice freshness to the dish.