A line bound to be written about Spanish dish (6)
I believe the answer is:
paella
'spanish dish' is the definition.
(paella is a type of Spanish dish)
'a line bound to be written about' is the wordplay.
'line' becomes 'l' (used when specifying particular lines from a poem).
'bound' becomes 'leap' (synonyms).
'to be written about' is a reversal indicator.
'a'+'l'+'leap'='alleap'
'alleap' written backwards gives 'PAELLA'.
(Other definitions for paella that I've seen before include "Make stew" , "Meal" , "Al, leap into the Spanish dish" , "Spanish dish based on saffron rice" , "Saffron-flavoured rice dish" .)