Stupid mistake to make bread (7)
I believe the answer is:
bloomer
I believe this is a double definition.
'stupid mistake' is the first definition.
(I've seen this before)
'bread' is the second definition.
(type of loaf of bread)
'to make' is the link.
(Other definitions for bloomer that I've seen before include "Stupid error (colloq.)" , "Stupid mistake" , "that's made with flour!" , "made by a baker" , "Mistake (colloq.), loaf" .)