Slow as a bicycle featuring hot stuff! (6)
I believe the answer is:
wasabi
'hot stuff' is the definition.
(I've seen this in another clue)
'slow as a bicycle featuring' is the wordplay.
'featuring' indicates the answer is hidden within the clue.
'WASABI' can be found hidden inside 'slow as a bicycle'.
(Other definitions for wasabi that I've seen before include "Pungent green paste used in Japanese cuisine" , "Strong-tasting Japanese paste" , "Hollyhock" , "Sushi condiment" , "'Japanese plant, often eaten with raw fish (6)'" .)