Kuchen im Himmel (pie in the sky )

Na, Süßer!

In German pie simply means "cake". I do not understand how in English pie is not cake? There is the word Torte which is a more cream or fruit filled kind of cake, but it is still a cake (a layer cake with a filling of custard, cream jelly). I know he did not mean Pi because Pi is squared and a piece of pie is most likely a triangle. I suppose you can say: easy as pie, extremely easy or simple. 
The word pie itself is pretty old. It’s recorded by the 1300s. The slang pie, however, is much more recent. It’s evidenced by the 1990s. A dealer would get a kilogram (kilo) of cocaine and cut it up for lower-level dealers to distribute—like a regular pie, just for a very different kind of craving. This pie was first just used as a reference to drugs by those in the urban drug-dealing community. It spread to a wider audience when black hip-hop artists incorporated the drug-dealing lingo into their hit songs.

pie means WHAT????

English is confusing you know...pie could also mean pizza. Why not call it pizza? There is cutie pie and also the female well you know the part, may be called that as well. 

Here is the true definition of a pie:
A pie is a baked dish which is usually made of a pastry dough casing that covers or completely contains a filling of various sweet or savory ingredients. Pies are defined by their crusts. A filled pie, has pastry lining the baking dish, and the filling is placed on top of the pastry but left open.