Pie filling (7)
I believe the answer is:
custard
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">pie filling</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for custard that I've seen before include "Egg/milk bake" , "Sweet sauce made with milk and eggs" , "Yellow sauce" , "-- Pie; -- apple" , "Pudding accompaniment" .)