Smashing day with breadbasket is sanctuary (6)
I believe the answer is:
adytum
'is sanctuary' is the definition.
(I've seen this before)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for adytum that I've seen before include "Temple sanctuary" , "inner sanctum" , "Inner room" , "sacred space" , "ancient sanctuary" .)