Customers, returning dessert, chose superior version (6,2)

'chose superior version' is the definition.
(trade up can mean to replace with a better version)

'customers returning dessert' is the wordplay.
'customers' becomes 'trade' (trade can mean customers or business).
'returning' says the letters should be written backwards.
'dessert' becomes 'pud' (short for pudding).
'pud' reversed gives 'dup'.
'trade'+'dup'='TRADED UP'