Cake layer (4)
I believe the answer is:
tier
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">cake layer</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 tier that I've seen before include "Plague" , "Wedding cake feature" , "Rank, level" , "Layer, rank" , "one doing Bond" .)