Not yet stirring filling of mint after producing pork pies (5,2)
I believe the answer is:
lying in
'producing pork pies' is the definition.
I can't tell whether this defines the answer.
'not yet stirring filling of mint after' is the wordplay.
'not yet stirring' becomes 'lying' (I am not sure about this - if you are sure you should believe this answer much more).
'filling of' means to look at the middle letters (the letters which fill the inside of the word).
'after' says to put letters next to each other.
The middle of 'mint' is 'in'.
'lying'+'in'='LYING-IN'
Can you help me to learn more?
(Other definitions for lying in that I've seen before include "being lazy" , "confinement" , "Staying abed - confined in childbirth" .)