Foodstuff from plant covering lake roughly to the west (7)
I believe the answer is:
treacle
'foodstuff' is the definition.
(treacle is a kind of foodstuff)
'plant covering lake roughly to the west' is the wordplay.
I cannot really see how this works, but
'lake' could be 'l' (geographical abbreviation) and 'l' is present in the answer.
'roughly' could be 'c' (circa) and 'c' is found in the answer.
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
'from' is the link.
Can you help me to learn more?
(Other definitions for treacle that I've seen before include "flattery" , "cloying stuff" , "Something sticky" , "Contrived sentimentality - sticky substance" , "Electra (anag)" .)