The first Kirk's opened in 1948. Although there have been facelifts over the years, the menu hasn't changed too much.

"We've had the same meat vendor since the very first day," Withers says. He won't reveal anything else, other than to say, "It's a butcher on the mid-peninsula." Withers describes the steakburgers as a "unique blend of different steaks ground together."

Since taking over 10 years ago, Withers has broadened Kirk's product line a bit. At that time, only the Cupertino restaurant offered French fries. Now they're available at all three.

"In a hamburger joint you ought to offer fries," Withers says. He's also added onion strings in Cupertino, plus a couple of salads, chicken sandwiches and a sausage patty sandwich. Another addition is nachos with cheese and crumbled bacon, which Withers says "is kind of a kid thing."

Despite the menu tweaks, it's the steakburgers and frankfurters that are Kirk's mainstay. Withers' favorite is "The Griller," which is served on a French roll with Swiss cheese and grilled onions. Among customers, the most popular item is the one-third pound steakburger with cheese.

Withers started eating at Kirk's 37 years ago. As he grew up, married and had children, he kept going back. But working in the electronics industry, Withers found he was traveling a lot.

"I was gone as my kids were growing up," he says.

Withers started thinking about what he wanted to do with the rest of his life.

"I didn't want to be in the restaurant business, but I did want to be in the Kirk's business," he says. "So I called the owner and eventually we worked out a deal."

Withers says he's tried to remain true to the original founder's vision. That means providing food he says is "the very best we can find. High quality. Very distinctive. We want people to know it's not fast food."

One Kirk's distinction is milkshakes and malts in every flavor imaginable. Banana, coffee and pineapple are on the menu, along with the traditional chocolate, vanilla and strawberry flavors. A full-scale condiment bar lets customers dress their burgers with pickles, lettuce, tomato, onions, peppers etc.

"It's easy for customers because the condiments are all out," Withers says.

Another key to Kirk's popularity is the grill itself. The three restaurants go through a whopping 40 tons of charcoal a year, giving Kirk's Steakburgers a distinctive flavor and maintaining a long-standing tradition. Withers sums it all up by saying, "Kirk's isn't cool. It's just Kirk's."

Kirk's in Cupertino is at 1330 South De Anza Blvd., 408.446.2988. It's open daily from 11 a.m. to 9 p.m.