Now, before you go and tell me that I've got it all wrong, I do actually know what this phrase means. But it was only a few years ago that I figured it out. And I still say it's poorly worded. It should be:
"Eat your cake and still have it afterwards."
Not as catchy perhaps, but at least it makes sense!
Maybe "have your cake and eat it too" seemed clear and unambiguous to the dyslexic or linguistically-incompetent person who coined it (or misheard it from the previous person in a game of Chinese Whispers).
Or maybe it was coined by someone living in a country where it was illegal to eat one's own cake. "Thou shalt not both posess cake and eat cake." For fear of being sent to prison, no one ate cakes, unless it was in illicit circumstances - bake-easies...
Enlighten me please.