If the quest for Asian groceries has led you to Hong Kong Market, the sprawling West Bank grocery, you may have noticed Mr. Bubbles Sandwich House, a colorful walk-up banh mi shop in its foyer. Now Mr. Bubbles is expanding with a second location in downtown New Orleans.

It will bring Vietnamese sandwiches and coffee drinks, while also adding an outlet for Dong Phuong bakery goods in the center of town.

This new Mr. Bubbles Café is expected to open by late May at 1441 Canal St. It’s a street level, storefront location within the New Orleans BioInnovation Center, a business incubator, which had previously been home to the sandwich shop Honey Loaf.

Brian Smith, who is opening the café with his girlfriend Thao Nguyen, said they were lured across the river by the prospects of rising downtown redevelopment. They’re aiming to fill a niche for quick breakfast, inexpensive lunch and catering platters for nearby offices and medical facilities.

Mr. Bubbles Café will have a more extensive menu than the West Bank original, adding spring rolls, more hot and chilled coffee and tea beverages and baked goods. Many of the pastries will be supplied by Dong Phuong, the revered bakery out in the far eastern reaches of New Orleans East that already provides Mr. Bubbles’ banh mi loaves.

“The focus is still on banh mi and bubble tea, but we’re adding to that,” said Smith.

The Mr. Bubbles menu follows a familiar script for Vietnamese sandwich shops, with a long list of banh mi varieties and a roster of frozen tea drinks with “bubbles” of marble-sized tapioca balls.

Mr. Bubbles has also added to the line up with its own creation: the crab boil hot sausage banh mi, a southeast Asia-to-southeast Louisiana crossover hit that packs a lot of spice. It will be part of the downtown menu too.

Nguyen’s parents, Canh and Nam, opened the first Mr. Bubbles in 2012 inside the Hong Kong Market complex. Like most local Vietnamese eateries it is a family affair, run with the help of the couple’s six children. The new Mr. Bubbles Café will be a next-generation family spinoff, operated by Nguyen and Smith on their own.

“We’re still involved in running the original, but this is ours and we’re really excited to see what we can do,” said Smith.

Mr. Bubbles is just the latest Vietnamese eatery to cross the river from the West Bank. Last year, Nine Roses expanded from Gretna to the French Quarter with its more casual Nine Roses Café.

And Pho Tau Bay, perhaps the best-known purveyor of Vietnamese flavors in the area, has a new location in the works a few blocks away from Mr. Bubbles Cafe, at 1565 Tulane Ave. This new Pho Tau Bay will replace its original Gretna restaurant, which was torn down for a seperate development project last year, though the owners have given no indication of when they may open.

Smith, for his part, thinks the proximity of other Vietnamese eateries downtown is a good thing because it expands familiarity with the flavors.

“When Pho Tau Bay was here (before Katrina), they showed people about Vietnamese food,” he said. “I think the area is ready for more of it.”

Mr. Bubbles Sandwich House

(at Hong Kong Market)

927 Behrman Hwy., Terrytown, 504-570-6377

Mr. Bubbles Cafe

(at New Orleans BioInnovation Center)

1441 Canal St.

Projected opening late May, 2016

Follow Ian McNulty on Twitter @IanMcNultyNOLA.