Cravings revealed by this, crossing entrance to Regent Street (7)
I believe the answer is:
thirsts
'cravings' is the definition.
(I've seen this before)
'this crossing entrance to regent street' is the wordplay.
'crossing' is an insertion indicator.
'entrance to' suggests taking the first letters.
'street' becomes 'st'.
The first letter of 'regent' is 'r'.
'r'+'st'='rst'
'this' going around 'rst' is 'THIRSTS'.
'revealed by' is the link.
(Other definitions for thirsts that I've seen before include "needs water" , "Hungers!" , "Cravings" .)