Make favourable mention of what one may have done here? (3,2,1,4,2,3)

'make favourable mention' is the definition.

'of what one may have done here?' is the wordplay.
I cannot quite understand how this works, but
'of' could be 'o' and 'o' is found within the answer.
'one' could be 'i' (Roman numeral) and 'i' is present in the answer.
'done' could be 'u' and 'u' is found within the answer.
This explanation may well be incorrect...