Dismisses ice cream for a cake (4,5)
I believe the answer is:
drop scone
'cake' is the definition.
(I've seen this before)
'dismisses ice cream' is the wordplay.
'dismisses' becomes 'drops' ('drop' can be a synonym of 'dismiss').
'ice cream' becomes 'cone' (cone can refer to an ice cream cone).
'drops'+'cone'='DROP-SCONE'
'for a' acts as a link.
(Other definitions for drop scone that I've seen before include "Small and thick pancake" , "Girdlecake" , "Eating" , "Scotch pancake" , "cake" .)