Place vessels around large plot (3,5)
I believe the answer is:
Here is my best explanation:
'plot' is the definition.
'place vessels around large' is the wordplay.
'place' becomes 'lay' (laying is a kind of placing).
'vessels' becomes 'pans' (I've seen this in other clues).
'around' indicates putting letters inside.
'large' becomes 'l'.
'pans' placed around 'l' is 'plans'.