One who can confidently deliver chargrilled crab regularly (5)
I believe the answer is:
crier
This might be a double definition.
'one who can confidently deliver chargrilled' is the first definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'crab regularly' is the second definition.
The definition and answer can be both people as well as being singular nouns.
Perhaps there's an association between them I don't understand?
Can you help me to learn more?
(Other definitions for crier that I've seen before include "court official" , "Officer making announcement" , "Town announcer" , "See 8" , "There once was a town one" .)