Brittle savoury biscuit glazed and salted on the outside (7)
I believe the answer is:
pretzel
(Other definitions for pretzel that I've seen before include "Crisp salted biscuit" , "Curly savoury snack" , "Knotted crisp biscuit" , "Knot-shaped cracker" , "Crisp, salty knot-shaped biscuit" .)