Choose from last of desserts: decide (6)
I believe the answer is:
select
'choose' is the definition.
(I know that choose can be written as select)
'last of desserts decide' is the wordplay.
'last of' says to take the final letters.
'decide' becomes 'elect' (I've seen this in another clue).
The final letter of 'desserts' is 's'.
's'+'elect'='SELECT'
'from' is the link.
(Other definitions for select that I've seen before include "Carefully chosen; choose" , "Choose, being special" , "Choose from the elite?" , "Choose from several" , "Choose from a number of alternatives" .)