Vauxhall will supply 500 specially-converted Vivaro panel vans over the next two years, enabling Benjys to sell food and drinks from mobile locations around the country.
Vauxhall officials said the deal was the largest single order placed by a company operating in the retail sector this year.
The 1.9 DTi Vivaros have been adapted to include refrigeration units and catering equipment, a rear tailgate and a power take-off (PTO) unit which powers equipment on the vehicle.
Benjys' executives worked with Piper Design, specialists in racing car design, to design and patent their own exclusive vehicle. The van design allows it to provide a range of products from a hygienic environment. It can be opened up and turned into a fully functional shop within 30 seconds.
A fifth of the order will be delivered by the end of the year, with the remaining 400 being rolled out over the next two years.
Although Benjys will outright purchase the Vivaros, it plans to lease them back to franchisees, working under the Benjys Delivered name.
Benjys has already sold 50 franchises and Ian Rickwood, chief executive at Benjys, said: 'The van's design will provide a fundamental competitive advantage. Response from the franchise industry and potential franchisees has been much better than anticipated.'
John Piper, Piper Designs managing director, said: 'Nothing like this currently exists. We have taken our expertise from racing car design and applied it to produce the ultimate mobile retail vehicle.'
The van was unveiled at the National Franchise Exhibition last week.