Thanksgiving bowlful (4)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">thanksgiving bowlful</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for yams that I've seen before include "vegetables" , "Sweet potatoes" , "Roots" , "Edible tubers from the tropics" .)