Check under both ingredients of stew and mishmash (5-5)

'stew and mishmash' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.

'check under both ingredients' is the wordplay.
'check' becomes 'ch' (abbreviation).
'under' means one lot of letters go next to another.
'both ingredients' becomes 'hotchpot' (I can't explain this - if you can you should believe this answer much more).
'ch' put after 'hotchpot' is 'HOTCH-POTCH'.

'of' acts as a link.

Can you help me to learn more?