Starchy tuber (6)
I believe the answer is:
potato
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">starchy tuber</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for potato that I've seen before include "Tuberous vegetable" , "Vegetable - a hot one is trouble" , "Root vegetable" , "The humble spud" , "Root crop" .)