Animal picked up dessert (5)
I believe the answer is:
moose
'animal' is the definition.
(type of animal)
'picked up dessert' is the wordplay.
'picked up' indicates a 'sounds like' (homophone) clue.
'dessert' becomes 'mousse' (mousse is a kind of dessert).
'mousse' sounds like 'MOOSE'.
(Other definitions for moose that I've seen before include "North American deer" , "Ungulate" , "Animal" , "Large US deer" , "North American elk" .)