Go to pieces when making dessert (7)

I believe the answer is:
crumble
This clue might be a double definition.
'go to pieces' is the first definition.
(I've seen this in another clue)
'making dessert' is the second definition.
'crumble' can be an answer for 'dessert'. I am not certain of the 'making' bit.
'when' acts as a link.
Can you help me to learn more?
(Other definitions for crumble that I've seen before include "Break down, fall apart" , "Fall to bits; a pudding" , "Gradually disintegrate" , "Type of pudding - disintegrate" , "Break up - fruit dish" .)