Paths laid out over a large pitch (7)
I believe the answer is:
asphalt
'pitch' is the definition.
(pitch mixture for surfacing roads)
'paths laid out over a large' is the wordplay.
'laid out' indicates anagramming the letters.
'over' is an insertion indicator.
'large' becomes 'L' (eg in clothes sizes).
'paths' with letters rearranged gives 'aspht'.
'a'+'l'='al'
'aspht' enclosing 'al' is 'ASPHALT'.
(Other definitions for asphalt that I've seen before include "surface of path" , "Pitch surface" , "Paving material" , "Material for road surfacing etc" , "Road-surfacing material" .)