Long cake (6)
I believe the answer is:
eclair
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">long cake</span>' is the definition.<br/ ><span class="explanation-format__explanation">(type of cake)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for eclair that I've seen before include "Finger-shaped cake with cream filling" , "A relic (anag)" , "Long, individual cake" , "Choux pastry cream cake" , "Long (but not long-lasting) cake" .)