How meat's cooked, to a certain extent (8)
I believe the answer is:
somewhat
'to a certain extent' is the definition.
(I've seen this before)
'how meat's cooked' is the wordplay.
'cooked' is an anagram indicator.
'how'+'meats'='howmeats'
'howmeats' with letters rearranged gives 'SOMEWHAT'.
(Other definitions for somewhat that I've seen before include "Partially, to a degree" , "To a moderate extent" , "To an extent, a little" , "To some degree, sort of" , "Quite" .)