With little more than determination and a dream in her heart, single mom Taeko “Sandy” Iwashita left a secretarial job in 1966 to launch a restaurant. She had no business experience and, by her own account, “didn’t know how to cook at all.” Yet 50 years later, Sandy’s Drive In in Kealakekua still serves up local-style food at affordable prices to the Kona community.

That’s plenty to celebrate, and the restaurant did so in fine style Sunday, with chili bowls and birthday cake.

After all those years, at age 84, Iwashita is still running the place. She goes to the restaurant every day to take care of the books and cook the daily special. She’s come a long way since the early days, when she had to rely on her cooks to deliver the menu, which included basic fare such as hamburgers, teriyaki beef, fried chicken and mahi. Plates then were 95 cents.

“I had great girls,” she said. “One of them was so good she could taste raw meat and say, ‘Add more salt.’”

Their cooking skills rubbed off on the boss. These days, said her son, Aaron Ikeda, she cooks delicious food without even having to taste it.

But delivering the 50 or so items currently on the menu is no longer her sole responsibility. Today, Sandy’s is a three-generation endeavor involving Ikeda and granddaughter Kelsi Akahoshi. The trio’s system is one of support.

Ikeda says he’s there “to do basically whatever needs to be done,” from placing orders to maintaining the building to cutting meat. He moved home from Honolulu in 1980 and brought his experience as an assistant manager at Zippy’s to the business.

Akahoshi, his daughter, is gradually taking on more duties to ease Iwashita’s responsibilities.

“Grandma still runs the kitchen,” said the professional chef, who’s worked for Alan Wong’s, Nobu Waikiki and Trump International Hotel Waikiki. She returned to Kona in 2012. “She’s still the boss. I help her out where I can.”

That means whipping up plates of spaghetti, spareribs and baby back ribs, beef curry, stew, mochiko chicken and more, including sandwiches and breakfast items. Akahoshi has also added a few creations of her own, contemporary fusion items such as luau fries (topped with kalua pig, lomi tomato relish and poi) and bulgogi fries (sliced bulgogi and spicy aioli toppings).

It’s a fine balance, mixing the new into a menu of long-held favorites.

“The same people come in all the time, and I want to be sure to keep what they like, what they’ve been coming for all these years,” she said. “I’m also adding new things to bring in new customers.

“The challenge is people are used to eating what they like. I got scolded by one lady for making the luau fries. She said Hawaiian food should be served with rice, not french fries. Then she tried it and liked it. On the first day I made the bulgogi fries, we got two orders. Now, it’s like 20. It spread by word of mouth.”

When Iwashita opened the doors to Sandy’s on Aug. 8, 1966, she was motivated by financial need — her modest secretary’s salary wouldn’t put three children through college. Since she wasn’t trained in any way to run a restaurant, a three-day visit to Jumbo’s Drive-In on Oahu was arranged as a crash course.

“I only saw the workers running back and forth, back and forth,” she recalled. “What can you learn in three days?”

Somehow, she muddled through and found early success taking bento orders for construction workers building a new Kona Airport and hotels in Keauhou. School kids, families, traveling businesspeople and even tourists rounded out her customer base.

The restaurant moved in 1990 to its current site, still in Kealakekua. Through the years, she says, there have been financial ups and downs. But the business allowed her to achieve her goal. She sent Aaron to Northern Colorado University, daughter Beryl to Harvard University and son Daryl to the University of Hawaii at Manoa.

For Akahoshi, who’s created gourmet food in some of the state’s top restaurants, the benefits of cooking at Sandy’s is the intimacy that comes with feeding one’s own community.

“Even when I was working in fancier restaurants, I liked to cook family meals,” she said of the meals that restaurant staffs eat together before service begins. “I cooked what I like and then waited to see how people liked my food.

“Cooking here is like cooking family meals. I cook what I like to cook and then see what customers think. It’s nice; it’s a different feeling. Many of the staff has worked with us for years, so they have great relationships with customers. It’s a nice atmosphere.”

Ikeda says the secret to Iwashita’s success is that she cares about providing good-quality meals at a good price. “That’s her contribution,” he said.

He knows his mother well.

“I hate to go over $9.25,” she said, noting that many customers are lunch patrons who don’t want to spend much.

She’s particularly protective of the price of her bento box, filled with teriyaki, mahi, chicken wings, Spam and takuan, which she holds at $8.75.

“It’s special,” she said.