What you were baking when the oven fused? (10)
I believe the answer is:
shortbread
I'm afraid I can't explain this answer.
Can you help me to learn more?
(Other definitions for shortbread that I've seen before include "Brittle buttery cake" , "biscuits" , "sweet but easily crumbling" , "Crumbly biscuit rich in butter" , "Biscuit with plenty of butter" .)