After the blaze earlier this month put the Star Inn the City kitchens out of action until the new year, the business collaborated with Taylor's of Harrogate to open a Yorkshire Tea-branded 'Yorkshire Teapee' tent with a bar and seating area.
The festive attraction on the outdoor terrace was proving popular with customers - but now the restaurant's owners have revealed it was broken into and vandalised on Monday night, just days after opening to the public.
The criminals damaged both equipment and furniture inside the teepee, which has a firepit, fairy lights and a gin bar.
A statement on the Star Inn the City's Facebook page said:
"We have worked terribly hard to get back up and running for drinks service after a devastating fire in the roof void above our kitchen just over two weeks ago. Overnight our beautiful Teapee has been broken into and reckless damage caused to equipment and furnishings...we’d love to meet these people!
"Needless to say we aren’t feeling particularly festive right now although we promise we’ll get our act together in time for opening at 12 noon."
The incident caps off a terrible month for the eatery on the banks of the River Ouse, which is recommended by the Michelin Guide and run by top chef Andrew Pern.
The fire on November 9 caused extensive damage to the kitchen but the cause is not thought to be suspicious. The restaurant re-opened soon afterwards serving only drinks and snacks, and a full food service is expected to resume in January.
When the restaurant opened beside the scenic Museum Gardens in 2013, 5,000 bookings were made in the first 24 hours.