Lots can be supplied in extremes of penury (6)
I believe the answer is:
plenty
'lots' is the definition.
(I've seen this before)
'supplied in extremes of penury' is the wordplay.
'supplied' becomes 'lent'.
'in' indicates putting letters inside.
'extremes of' means to remove the middle letters (only the letters at the extremes of the word).
'penury' with its centre removed is 'py'.
'lent' going within 'py' is 'PLENTY'.
'can be' acts as a link.
(Other definitions for plenty that I've seen before include "Many" , "Amplitude or abundance" , "Copiousness" , "A great deal" , "A full supply - lots" .)