It may not be as over-hyped and picture-worthy as the salted egg croissant, but the shio pan is no less trendy.

Shio pan - shio means salt and pan means bread in Japanese - is certainly not the usual soft and sweet bun that is often sold in bakeries here.

Instead, it is decidedly savoury from the salt sprinkled on its golden crunchy top. It has a slightly chewy dough with a buttery filling, and is best eaten warm and toasted.

The bread is said to have originated in Pain Maison, a bakery in Ehime Prefecture in late 2014. Since then, it has gained popularity, with other bakeries in Japan rolling out their own versions.

In Singapore, at least six bakeries have been turning out these buns since last year and businesses note that the buns have become top sellers in the past six months.

Japanese boulangerie Donq (www.facebook.com/donqbakery) in Takashimaya Shopping Centre was one of the early ones to introduce the salted bun last year.

Simply called "salt and butter bread" ($2), the bun's added edge over others is that its base is fried until crisp in melted butter.

Donq's store manager Chinami Date, 33, says: "The buns are baked three to five times a day and we can sell up to 150 pieces on weekends. Shio pan is also best combined with chocolate and fruit."

The salty butter bun ($2) at Duke Bakery (www.dukebakery.sg) has also been well-received since its launch in September last year.

Compared to the others, Duke's bun is slightly fluffier and bigger. The dough is made with yeast from fermented fruit, sea salt and butter.

Bakery chain BreadTalk launched its Himalayan pink salt roll ($1.50 or $4 for three, www.breadtalk.com.sg) in November last year, after its sister bakery chain Bread Society (www.breadsociety.com.sg) launched it in the first quarter of last year.

Since then, the Japanese-inspired bun has become one of the best- sellers for the brand.

A BreadTalk spokesman says: "We believe that it is difficult to stop at just one roll because of its addictive chewiness and crispy texture, complemented by the fragrance of the buttered roll. The Himalayan pink salt also leaves no salty aftertaste."

Other bakeries selling the savoury bread include Johan Paris (shio roll bread, $1.40; outlets at Isetan Scotts, and Isetan Westgate); St. Leaven and Four Leaves (sio pan, $1.40, www.four leaves.com.sg) and Crown Bakery in Bukit Timah (salted butter roll, $1.90, www.crown bakery.com.sg).

Since she discovered shio pan at Donq a few months ago, the bun has been on housewife Wendy Leong's shopping list whenever she buys bread.

The 52-year-old says: "I'm not a fan of sweet buns so this salted bun is right up my alley. It is not too salty and absolutely delicious with the buttery centre."

Sales assistant Heidi Lim, 27, likes the shio pan from Four Leaves bakery. "I noticed the bun as it has been promoted as a new item in the bakery and it was snapped up quickly after a fresh batch was put out.

"It is a nice, savoury snack during the day when I'm busy at work and have no time for a proper meal. The salt pairs nicely with the rich butter," she says.