Fruit gelato served up without nuts on top (7)
I believe the answer is:
tangelo
'fruit' is the definition.
(I know that tangelo is a fruit)
'gelato served up without nuts on top' is the wordplay.
'served up' indicates anagramming the letters.
'without' is an insertion indicator ('without' can be similar in meaning to 'outside').
'on top' suggests taking the first letters.
The first letter of 'nuts' is 'n'.
'gelato' is an anagram of 'tagelo'.
'tagelo' placed around 'n' is 'TANGELO'.
(Other definitions for tangelo that I've seen before include "sharp cross" , "Hybrid fruit; eat long (anag.)" , "fruitful merger?" , "Mixed fruit" , "Citrus hybrid - goal net (anag)" .)