Supports pastry with right sourdough used initially (5)
I believe the answer is:
piers
'supports' is the definition.
(pier is a kind of support)
'pastry with right sourdough used initially' is the wordplay.
I cannot quite understand how this works, but
'pastry' could be 'pie' (pie is a kind of pastry) and 'pie' is found within the answer.
'right' could be 'r' (common abbreviation) and 'r' is found within the answer.
A single letter 's' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for piers that I've seen before include "Jetties" , "Supports for bridge spans" , "Old ploughman" , "Landing stages" .)