Add the flour and pepper flakes to a large zip lock bag, add a few livers, seal the bag and shake to coat the liver, remove to a plate and repeat to coat all the liver.

Heat the olive oil in a large non stick pan and when heated, fry the livers for 2-4 minutes on each side, depending if you want them pink inside or well done. Season with salt and pepper as desired while frying.

Remove the liver to a plate and cover to keep warm, remove the pan from the burner and let it cool for 30 seconds to minute, then add the balsamic vinegar and return to the burner.

Add the butter and mix well, when combined, return the liver to the pan and coat them with the sauce and heat them through.