I'm Trying to Fix this Adage

Wrong but used 99% of the time these days: "You can't have your cake and eat it too."

Yes, yes you can. That's how it works. You can get a cake, you have it, and then you eat it, just like this little nugget.

The saying is: "You can't eat your cake and have it too."

You see? If you eat it, you won't have it anymore. 

Except of course if you're speaking in lesbian euphemistic terms, in which case it's an all you can eat and have it too buffet.