Simple dish — not as snob ate in mess (5,2,5)
I believe the answer is:
beans on toast
'simple dish' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.
'not as snob ate in mess' is the wordplay.
'in mess' is an anagram indicator.
'not'+'as'+'snob'+'ate'='notassnobate'
'notassnobate' with letters rearranged gives 'BEANS ON TOAST'.
Can you help me to learn more?
(Other definitions for beans on toast that I've seen before include "Pulses, tomato sauce and grilled bread" , "vegetarian option!" , "Such a snack" .)