Metal is delicious, getting terribly bitter (9)
I believe the answer is:
ytterbium
'metal' is the definition.
(I know that ytterbium is a type of metal)
'delicious getting terribly bitter' is the wordplay.
'delicious' becomes 'yum' (I can't explain this - if you can you should believe this answer much more).
'getting' is an insertion indicator.
'terribly' indicates an anagram.
'bitter' anagrammed gives 'tterbi'.
'yum' enclosing 'tterbi' is 'YTTERBIUM'.
'is' acts as a link.
Can you help me to learn more?
(Other definitions for ytterbium that I've seen before include "metal" , "Rare-earth element" , "SEVENTY" , "Element with symbol Yb" , "Atomic number 70" .)