A sad, a bleak king ordered pudding (5,6)
I believe the answer is:
baked alaska
'pudding' is the definition.
(I've seen this before)
'a sad a bleak king ordered' is the wordplay.
'king' becomes 'K' (abbreviation for king in chess).
'ordered' indicates anagramming the letters.
'a'+'sad'+'a'+'bleak'+'k'='asadableakk'
'asadableakk' anagrammed gives 'BAKED ALASKA'.
(Other definitions for baked alaska that I've seen before include "pudding" , "Hot and cold sweet" , "Ice cream sponge and meringue dessert" , "Cake and ice cream dessert" , "Ice-cream and meringue dessert" .)