Add sugar (7)
I believe the answer is:
sweeten
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">add sugar</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for sweeten that I've seen before include "Add, eg, sugar to" , "Make less bitter" , "Modify" , "Make more palatable" , "Add sugar etc" .)