Fizzy drink accompanies extremely salty dish (5)
I believe the answer is:
popsy
'dish' is the definition.
(I've seen this before)
'fizzy drink accompanies extremely salty' is the wordplay.
'fizzy drink' becomes 'pop' (pop is a type of fizzy drink).
'accompanies' says to put letters next to each other.
'extremely' means to remove the middle letters (only the extremes of the word are used).
'salty' with its middle removed is 'sy'.
'pop'+'sy'='POPSY'
(Other definitions for popsy that I've seen before include "dish" , "Attractive girl" .)