Everybody eats at Mo’s Lunch. Since the restaurant owned by Austin Racine and Maura Martin opened at the Portuguese American Club in November 2020, it has become an Island mainstay.

Mo’s continues the long culinary partnership of Mr. Racine and Ms. Martin. They met while working at the Art Cliff Diner in 2005 and worked together at Cafe Moxie, State Road Restaurant and Noman’s. When opening Mo’s, they based the menu around an item they have individually been obsessed with: sandwiches.

“It’s a labor of love,” Mr. Racine said.

But the menu doesn’t begin and end with sandwiches for Mr. Racine and his kitchen crew. Onion rings have a following and leftovers fuel creativity. Apple butter from a recent Southern-themed night was repurposed for donuts. Korilee Connelly completes the team by baking cookies, brownies, pies and other sweets.

On Wednesday nights, the themed dinners include Moroccan, Indian, Southern and Asian foods. Mo’s is open five days a week and averages approximately 600 orders a week.

In addition to fresh foods, the secret to success is straightforward.

“We’re going for heavy portions.” Ms. Martin said. “Big portions and keeping the prices low. It’s important that we cater to locals. We want people to get value for their money.”

When the P.A. Club first approached them about running a pop-up restaurant, the duo agreed to two nights a week. By Jan. 2021, things were going well and the club’s management asked if they’d like to lease the space long-term.

A friendly partnership with the P.A. Club management makes the situation ideal, they said. Low overhead means that Ms. Martin and Mr. Racine can keep prices low and bring in a high volume of customers. A nod to the club’s roots is a snack plate of tinned fish from Portugal served with sourdough toasts, housemade aioli and pickled vegetables.

Making everything fresh means long work days. But both Ms. Martin and Mr. Racine said they love what they’re doing. They’re creating menus that explore foods they couldn’t serve at other venues. It also makes a difference that they work for themselves.

But the most gratifying aspect of owning their own restaurant is feeding and seeing the regulars. Hospital workers, landscapers and families all pass through Mo’s on a regular basis.

“The people are the best part of what we’re doing,” Ms. Martin said. “I’ve met so many people who have become our regulars.”