Fruit is extra large, see? (7)
I believe the answer is:
morello
'fruit' is the definition.
(morello is a kind of fruit)
'extra large see?' is the wordplay.
'extra' becomes 'more' (both can mean additional).
'large' becomes 'L' (eg in clothes sizes).
'see?' becomes 'lo' (archaic exclamation meaning 'look!').
'more'+'l'+'lo'='MORELLO'
'is' acts as a link.
(Other definitions for morello that I've seen before include "Variety of sour cherry" , "Dark-red variety of cherry" , "Small, dark, sour cherry" , "Cherry's" , "cherries" .)