It is a rum concoction that produces spirit raising dessert (8)
I believe the answer is:
tiramisu
'dessert' is the definition.
(I've seen this before)
'it is a rum concoction' is the wordplay.
'it is' becomes 'itis'.
'concoction' indicates anagramming the letters.
'itis'+'a'+'rum'='itisarum'
'itisarum' is an anagram of 'TIRAMISU'.
'that produces spirit raising' is the link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for tiramisu that I've seen before include "Rich dessert, it is a rum (anag.)" , "Sweet" , "Dessert (Italian "pick me up")" , "Italian sponge dessert" , "Dessert -- is it arum? (anag)" .)