Crawler in charge of jelly (5)
I believe the answer is:
aspic
'jelly' is the definition.
(I know that aspic is a type of jelly)
'crawler in charge' is the wordplay.
'crawler' becomes 'asp' (I can't explain this - if you can you should give a lot more credence to this answer).
'in charge' becomes 'ic' (abbreviation for 'in charge').
'asp'+'ic'='ASPIC'
'of' acts as a link.
Can you help me to learn more?
(Other definitions for aspic that I've seen before include "Savoury jelly for coating meats and eggs" , "Preservative jelly" , "Stock set with food" , "Lavender" , "Savoury meat or fish jelly" .)