Clue: Special ham/Branston sandwich filling – that sounds moreish! (8)
Answer: ALHAMBRA
Explanation: Definition: that sounds moreish

Hidden in [*sandwich filling*] "speci**AL HAM BRA**nston"
 
*Although I can see what Julius is doing here, I don't like it. The positioning of the homophone indicator "that sounds" implies that ALHAMBRA is the homophone, which it is not.