Breadhead's snack? (8)
I believe the answer is:
doughnut
'snack?' is the definition.
(doughnut is a type of snack)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for doughnut that I've seen before include "Small circular cake" , "Sweet circular snack" , "Toroid" , "Jam-filled cake" , "Fried batter cake" .)