As yet ham-fisted starter in the bakery (5)
I believe the answer is:
yeast
'the bakery' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
'as yet ham-fisted starter' is the wordplay.
'as yet' can be anagrammed to 'YEAST'.
But, I'm not sure how the anagram is indicated.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for yeast that I've seen before include "Fungus used to ferment sugar" , "lifting agent" , "What makes bread rise" , "Baker's ingredient" , "Agent for making bread" .)