Mouthwatering pie, with tons for papa (5)
I believe the answer is:
tasty
'mouthwatering' is the definition.
(I've seen this in another clue)
I don't understand the rest of the clue.
(Other definitions for tasty that I've seen before include "Toothsome" , "Appetising, having pleasant flavour" , "Having good flavour" , "Pleasantly flavoured" , "Delicious" .)