Whether it's the sort with the classic flaky casing, the Portuguese variety, with a caramelised top, or the ones with shortcrust pastry, egg custard tarts are big business in Hong Kong.

See also: The great egg tart hunt, and other Hong Kong bakery treats

Now a new take on the treat has arrived: the Japanese cheese tart looks like the Hong Kong egg tart, but has a cheese mousse - made from two Hokkaido cream cheeses and one French variety - encased in crispy pastry.

Created at the Kinotoya Bakery, in Hokkaido, Japan, by Shintaro Naganuma, the eldest son of the shop's founder, the tart has been a hit across Japan.

In 2013, Naganuma opened BAKE, his own line of cake shops, and the first overseas branch arrived at Sogo, Causeway Bay, in August. Although the initial waiting time of two hours has subsided, Post Magazine had to queue for 75 minutes one recent Thursday afternoon to sample a cheese tart.

"It is the double-bake method that makes the cheese tart special," says Jo Wong Yee-man, office manager at BAKE. "First the tart is baked, then the cheese is poured into it in Japan. Then, in Hong Kong, it is baked for the second time at 200 degrees.

"If the tart is not baked long enough, it is not crunchy enough; if the cheese is baked too long, the molten filling doesn't flow."

One tart costs HK$20 and a box of six is HK$110, with a limit of 12 tarts per day per customer.