Among trees plan a delightful walk (9)
I believe the answer is:
esplanade
'walk' is the definition.
(I know that esplanade is a type of mall)
'among trees plan a delightful' is the wordplay.
'among' says the answer is hidden in the clue.
'ESPLANADE' is hidden within 'trees plan a delightful'.
(Other definitions for esplanade that I've seen before include "Long wide pavement next to a beach" , "Open, level space for walks or drives" , "Seafront walk" , "Seaside walkway" , "place for a stroll" .)