The last ice-cream portion is bigger, potentially (7)
I believe the answer is:
elastic
'portion is bigger potentially' is the definition.
I can't judge whether this defines the answer.
'the last ice-cream' is the wordplay.
'cream' indicates anagramming the letters (letters blended or creamed into a new order).
'last'+'ice'='lastice'
'lastice' anagrammed gives 'ELASTIC'.
Can you help me to learn more?
(Other definitions for elastic that I've seen before include "Giving" , "Flexible rubbery strip" , "Something stretchy" , "Flexible (material)" , "Kind of band" .)