Keep quiet about my family's Douglas making bread (9)
I believe the answer is:
sourdough
'bread' is the definition.
(sourdough bread is a kind of bread)
'keep quiet about my family's douglas' is the wordplay.
'keep quiet' becomes 'sh' (as in shushing someone).
'about' means one lot of letters goes inside another.
'my family's' becomes 'our' (belonging to our family).
'douglas' becomes 'doug' (I can't explain this - if you can you should believe this answer much more).
'our'+'doug'='ourdoug'
'sh' placed around 'ourdoug' is 'SOURDOUGH'.
'making' acts as a link.
Can you help me to learn more?
(Other definitions for sourdough that I've seen before include "Leaven for making bread" , "Type of bread" , "Fermenting bread mixture - odour hugs (anag)" .)