A dish alas spoilt by hundreds (5)
I believe the answer is:
salad
'a dish' is the definition.
(type of meal or dish)
'alas spoilt by hundreds' is the wordplay.
'spoilt' is an anagram indicator.
'by' is a charade indicator (letters next to each other).
'hundreds' becomes 'd' (I've seen this in other clues).
'alas' with letters rearranged gives 'sala'.
'sala'+'d'='SALAD'
(Other definitions for salad that I've seen before include "vegetarian dish" , "Mixed food" , "Raw, green, veg" , "Green, potato, Russian or Waldorf?" , "Mainly raw cold dish" .)