Delicious salami in the soup, sibling tucking in (9)
I believe the answer is:
ambrosial
'delicious' is the definition.
(ambrosia was the mythical food of the Greek gods)
'salami in the soup sibling tucking in' is the wordplay.
'in the soup' indicates an anagram (soup can mean a mixture).
'sibling' becomes 'bro' (I've seen this before).
'tucking in' indicates putting letters inside.
'salami' is an anagram of 'amsial'.
'amsial' placed around 'bro' is 'AMBROSIAL'.
(Other definitions for ambrosial that I've seen before include "Heavenly" , "Delightful" , "delicious" , "Divine" , "Like special food" .)