Assuming you like pie (or pi)...
Can you eat your pie and have it, too?
It's more about the sentence than the food! Most people say it backwards.
From Wikipedia:
The phrase's earliest recording is from 1546 as "wolde you bothe eate your cake, and have your cake?" (John Heywood's "A dialogue Conteinyng the Nomber in Effect of All the Prouerbes in the Englishe Tongue") alluding to the impossibility of eating your cake and still having it afterwards. The modern version (where the clauses are reversed) is a corruption which was first signaled in 1812.