Slice of pear muffin provides a winter warmer (7)
I believe the answer is:
earmuff
'a winter warmer' is the definition.
(I've seen this before)
'slice of pear muffin provides' is the wordplay.
'slice of' says the answer is hidden in the clue.
'EARMUFF' is hidden in the letters of 'pear muffin provides'.
(Other definitions for earmuff that I've seen before include "(One of two) protecting against cold or noise in the hearing organ ..." , "Lug warmer" , "One of a pair for warming the side of the head" , "Pad to keep lug warm" , "Warmer worn on head" .)