E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
The books have been cooked. The ledger and other trade books have been tampered with, in order to show a balance in favour of the bankrupt. The term was first used in reference to George Hudson, the railway king, under whose chairmanship the Eastern Counties Railway accounts were falsified. The allusion is to preparing meat for table.