Standard plan to include Southern cheese (8)
I believe the answer is:
parmesan
'cheese' is the definition.
(Parmesan is an example)
'standard plan to include southern' is the wordplay.
'standard' becomes 'par' (I've seen this before).
'plan' becomes 'mean' (**).
'to include' means one lot of letters goes inside another.
'southern' becomes 's' (abbreviation).
'mean' enclosing 's' is 'mesan'.
'par'+'mesan'='PARMESAN'
(Other definitions for parmesan that I've seen before include "that grates" , "Cheese for grating" , "Spearman (anag) - cheese" , "Hard dry cheese, often grated" , "Hard dry Italian cheese" .)