LISBON: As Lisbon gears up for a long visit by Pope Francis next week, a local pastry shop has rolled out a brand-new treat to mark the occasion: a cookie with the pontiff's picture on it that is already selling fast.

The idea began as an in-house joke between one of the owners of Balcao do Marques, Fernando Santos, and his pastry chefs. They are now making up to 120 per day and hope to sell thousands at 2.20 euros ($2.43) a piece during Francis's Aug. 2-6 stay in the city.

The city-centre pastry shop is close to one of the venues where Francis will attend World Youth Day, a global gathering of young Catholics that runs from Aug. 1-6. Authorities expect more than one million people to attend.

"The idea has been brilliant," 49-year-old Santos said. "Everyone thinks (it's...) quite funny." People have been stopping by the pastry shop's window display to take pictures of the cookies to post on social media, he added.

Their design features an edible printed image of the pope set on a home-made cookie decorated with icing and coloured sugar sprinkles.

Although Francis has a busy schedule, Santos hopes he'll drop by to try one. "He is invited...it's close by and he just has to come down."