Flip large flans, that's the trick! (9)
I believe the answer is:
stratagem
'the trick' is the definition.
(thesaurus)
'flip large flans' is the wordplay.
'flip' is a reversal indicator.
'large' becomes 'mega' (I can't explain this - if you can you should give a lot more credence to this answer).
'flans' becomes 'tarts' (I've seen this before).
'mega'+'tarts'='megatarts'
'megatarts' written backwards gives 'STRATAGEM'.
'that's' is the link.
Can you help me to learn more?
(Other definitions for stratagem that I've seen before include "Start game with cunning plan" , "Ploy - start game (anag)" , "way to outwit opponent" , "Scheme to outwit an opponent" , "could be a trick" .)