Gruel I cooked is less appealing (6)
I believe the answer is:
uglier
'less appealing' is the definition.
(I've seen this in another clue)
'gruel i cooked' is the wordplay.
'cooked' indicates anagramming the letters (letters cooked into a new form).
'gruel'+'i'='grueli'
'grueli' with letters rearranged gives 'UGLIER'.
'is' is the link.
(Other definitions for uglier that I've seen before include "More 14 down" , "Less pleasing to look at" , "More displeasing to the senses" , "More offensive to look at" , "Less beautiful" .)