Jam? In tagliatelle? (8)
I believe the answer is:
tailback
'jam? in tagliatelle?' is the definition.
The answer and definition can be both acts as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
This is all the clue.
Can you help me to learn more?
(Other definitions for tailback that I've seen before include "Traffic jam" , "Sort of jam" , "Lack a bit (anag.)" , "Queue of cars" , "Long queue of traffic" .)