Cooks tofu in a stew, admitting starter of turkey is unavailable (3,2,5)
I believe the answer is:
out of stock
'unavailable' is the definition.
(similar in meaning)
'cooks tofu in a stew admitting starter of turkey' is the wordplay.
'in a stew' is an anagram indicator.
'admitting' means one lot of letters goes inside another (admit can mean to welcome in or accept).
'starter of' suggests taking the first letters.
The initial letter of 'turkey' is 't'.
'cooks'+'tofu'='cookstofu'
'cookstofu' is an anagram of 'ouofstock'.
'ouofstock' going around 't' is 'OUT-OF-STOCK'.
'is' acts as a link.
(Other definitions for out of stock that I've seen before include "unavailable?" , "Not available, all sold" , "Not available for sale" , "Thus soup might be made" .)