What's missing from matzo (5)
I believe the answer is:
yeast
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">what's missing from matzo</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 yeast that I've seen before include "Androgynous" , "Fungi used in bakery" , "Brewer" , "fermenter" , "Baker's raising agent" .)