Topping stuff from J Trent's collaborator? (6)
I believe the answer is:
thatch
'topping stuff' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps you can see an association between them that I can't see?
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for thatch that I've seen before include "Natural roof cover" , "Alternative to lead roof" , "unusual roof" , "Plant stalks as roofing material" , "Old-fashioned roof covering material" .)