The purpose of the pies is to force the masses to become addicted to their incredibly tasty flavor to the point where they can't stop eating them, causing them to become too fat and lazy to defend themselves, thus allowing Hector Con Carne to easily take over the world without opposition.
According to Ghastly, the pie's crust is made from micro tiny carbon iron fiber coils and the filling is mainly comprised of lard, as well as fattening and tasty oils. Once the filling is ready, she pours it into a giant tank and then she throws in a giant buckyball that's not too soft and not too dense. She then begins mixing it with a giant spoon and finishes its preparation by marching on the batter with her boots (since the batter was too thick for the spoon). Once the filling and crust are ready she bakes the pie until it froths and boils.
She claims that the reason the pie is so addictive and highly adored is not because of any nefarious chemicals, but because the secret ingredient is love.