Dessert pudding (7)
I believe the answer is:
tapioca
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">dessert</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >'<span class="explanation-format__original">pudding</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(tapioca pudding is a kind of pudding)</span><br/ ><br/ ></span>
(Other definitions for tapioca that I've seen before include "I act OAP (anag) - edible substance made from cassava" , "Starch from cassava used in making puddings" , "it thickens" , "Pudding made from an extract of cassava" , "Foodstuff used as a thickener" .)