Melt the ice with excellent - no ace - Sunday meal (7)
I believe the answer is:
defrost
'melt the ice' is the definition.
(I've seen this in another clue)
'excellent no ace sunday meal' is the wordplay.
'excellent' becomes 'def' (old-fashioned term for excellent).
'no' suggests deleting specific letters.
'ace' becomes 'a' (abbreviation).
'sunday meal' becomes 'roast' (I've seen this before).
'roast' with 'a' removed is 'rost'.
'def'+'rost'='DEFROST'
'with' is the link.
(Other definitions for defrost that I've seen before include "Thaw (frozen food)" , "Make free of ice" .)