Thanks, say, about dish (5)
I believe the answer is:
satay
'dish' is the definition.
(I have seen 'Indonesian dish ' mean 'satay' so perhaps 'dish' could also mean 'satay')
'thanks say about' is the wordplay.
'thanks' becomes 'ta' (UK informal version of 'thank you').
'about' means one lot of letters goes inside another.
'ta' put inside 'say' is 'SATAY'.
(Other definitions for satay that I've seen before include "Malaysian or Indonesian dish of grilled food with peanut sauce" , "Spicy Malaysian sauce" , "Eastern skewered dish" , "spicy dish" , "spicy sort of meat" .)