More mouth-watering (7)
I believe the answer is:
tastier
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">more mouth-watering</span>' is the definition.<br/ ><span class="explanation-format__explanation">('tasty' can be a synonym of 'mouth-watering')</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for tastier that I've seen before include "Having a more pleasant flavour" , "More attractive" , "More flavoursome" , "More palatable" , "More appetising" .)