Dish with Castro regularly causing tricky problem (3,6)
I believe the answer is:
hot potato
'tricky problem' is the definition.
(I've seen this before)
'dish with castro regularly' is the wordplay.
'dish' becomes 'hotpot' (I've seen this before).
'with' means one lot of letters go next to another.
'regularly' means one should take alternating letters (regularly take one letter, leave next etc.).
The alternating letters of 'castro' are 'ato'.
'hotpot'+'ato'='HOT POTATO'
'causing' is the link.
(Other definitions for hot potato that I've seen before include "Topical, dangerous, issue" , "troublesome affair" , "A difficult situation" , "Top hat too (anag)" , "Awkward thing" .)