Something starchy in this pudding (4)
I believe the answer is:
spud
'something starchy' is the definition.
(spud means a potato - potatoes are starchy)
'in this pudding' is the wordplay.
'in' indicates a hidden word.
'SPUD' is hidden within 'this pudding'.
(Other definitions for spud that I've seen before include "Potato (colloq.)" , "one's eyed" , "Tattie" , "King Edward, e.g." , "Charlotte perhaps" .)