Material originally sewn into each frill, one of two pads (7)
I believe the answer is:
earmuff
'one of two pads' is the definition.
(one of two pads worn on the ears)
'material originally sewn into each frill' is the wordplay.
'originally' indicates taking the first letters.
'sewn into' is an insertion indicator.
'each' becomes 'ea'.
'frill' becomes 'ruff' (a ruff is a frill worn round the neck).
The first letter of 'material' is 'm'.
'ea'+'ruff'='earuff'
'm' inserted within 'earuff' is 'EARMUFF'.
(Other definitions for earmuff that I've seen before include "Warmer worn on head" , "Pad to protect part of head from cold" , "One of a pair for warming the side of the head" , "(One of two) protecting against cold or noise in the hearing organ ..." , "Pad to keep lug warm" .)