The company said the deal with Mansfield Traquair would run through to the next decade. It has been working with the former church for more than 11 years.
Under the contract, a permanent team from Heritage Portfolio will be based within the historic venue, which has been described as one of Edinburgh’s hidden gems.
Meanwhile, the catering firm has extended its contract with Lennoxlove House, home of the Duke of Hamilton in Haddington, East Lothian.
Heritage executive director, Ian D’Annunzio Green, said: “Over the last decade we have built a reputation for working within heritage properties as an exclusive partner delivering exceptional dinners, events and weddings.
“Lennoxlove House and Mansfield Traquair represent the best in luxury venues in Scotland.”