Dark syrup (7)
I believe the answer is:
treacle
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">dark syrup</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 treacle that I've seen before include "Electra (anag)" , "Sweet sticky syrup" , "Viscous liquid" , "Dark viscous 11" , "Syrup-like substance" .)