They require absolute minimal cooking. It can be a bit worrying when you first start cooking with them - I know my first few batches were always over-cooked. If they are rubbery then you are cooking them too long. Let the pan get very hot, THEN add the butter, 30 seconds each side till each side has a slight crust/ caramelisation.
I wish I could afford them more often - I'd eat them every day *slobber*