To stew (6)
I believe the answer is:
braise
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">to stew</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for braise that I've seen before include "Stew in a closed pan" , "Cook slowly with little liquid in closed container" , "Fry then stew slowly" , "Fry then stew (meat)" , "13 across (anag)" .)