Brown jelly-like substance on round fruit (7)
I believe the answer is:
tangelo
'fruit' is the definition.
(tangelo is a kind of fruit)
'brown jelly-like substance on round' is the wordplay.
'brown' becomes 'tan' (tan is a kind of brown).
'jelly-like substance' becomes 'gel' (I've seen this before).
'on' means one lot of letters go next to another.
'round' becomes 'o' (round can mean a round object).
'tan'+'gel'+'o'='TANGELO'
(Other definitions for tangelo that I've seen before include "Citrus fruit hybrid" , "Hybrid fruit; eat long (anag.)" , "sharp cross" , "fruitful merger?" , "Citrus hybrid - goal net (anag)" .)