Mistake made by a baker (7)
I believe the answer is:
bloomer
This clue is a double definition.
'mistake' is the first definition.
(I've seen this before)
'made by a baker' is the second definition.
(I've seen this before)
(Other definitions for bloomer that I've seen before include "Big mistake" , "made by a baker" , "rose, say" , "Crusty loaf" , "Something from the baker" .)