Bear out one’s gone in to cook (6)
I believe the answer is:
Here is my best explanation:
'cook' is the definition.
(braising is a kind of cooking)
'bear out ones gone in' is the subsidiary indication.
'out' is an anagram indicator.
'ones' becomes 'is' ('I' can be a synonym of 'one').
'gone in' indicates putting letters inside.
'bear' is an anagram of 'brae'.
'brae' going around 'is' is 'braise'.
'to' is the link.
(Other definitions for braise that I've seen before include "Re bias (anag.)", "Heat slowly", "To stew", "Stew in a closed pan", "cook", "Cook by stewing", "Cook or stew slowly", "Fry and then stew (food)", "Fry then stew (meat)" and "13 across (anag)".)