Starter of tasty nettle delicacy (7)
I believe the answer is:
truffle
'delicacy' is the definition.
(truffle is a kind of delicacy)
'starter of tasty nettle' is the wordplay.
'starter of' indicates taking the first letters.
'nettle' becomes 'ruffle' (ruffling is a kind of nettling).
The initial letter of 'tasty' is 't'.
't'+'ruffle'='TRUFFLE'
(Other definitions for truffle that I've seen before include "Witty remark" , "Fretful for tasty underground fungus" , "Edible fungus -- chocolate sweet" , "Fungus, a delicacy" , "Sweet - edible fungus growing underground" .)