Last year, I asked Marchetti what was in that pink sauce.

“If I told you, I’d have to kill you,” he growled.

C’mon, Gino.

“Okay," he relented. "It was ketchup and mayonnaise.”

The first of the “new” Gino’s opened last weekend, in King of Prussia, Pa., selling seven-ounce, double-decker burgers, chicken, fries and shakes. On any given afternoon there, you’ll find Marchetti, 84, fussing about in the kitchen, frying up patties and tweaking recipes to try and please the most discerning palate.

“The other day, I worked the grill for almost two hours,” he said. “All of the (employees) there are new, so it’s important that I get in there and cook, and tease them, and make them feel good.”

Half a century ago, he did the same at his burger joints in Baltimore, starting with the first one, on North Point Road in Dundalk, in 1959. Back then, Marchetti spent his days carving out a reputation as the best pass-rusher in football history, and his nights grilling food in a grease-spattered kitchen. Patrons would gawk through the glass at the All-Pro lineman flipping burgers, hoping for a chance to meet the sandwich’s namesake. Marchetti would wave and keep on flipping.

“That’s the part of the business that I really like,” he said. “I’m a nuts-and-bolts guy in the kitchen. They used to call me ‘Coach’ (in the galley) back then. They do it now, too.”

Unlike the original Gino’s, which had grown into a nationwide chain of 469 drive-ins by 1982 when it was sold to Marriott International for $48 million, Marchetti has no financial stake here. He’s the face of the business, an octogenarian poster boy coaxed out of retirement to lend his name to the venture.

Why?

“I’m an old man, sitting around and not doing a helluva lot,” he said. “I’m a consultant, an adviser. I develop recipes. Here, you can’t just throw a hamburger on the grill and cook it, like you do in your backyard.

“I’ve come up with a pretty good chicken sandwich too, with a little spicy taste.”

One thing he won’t do is wear an apron.

“Employees tease me about that,” said Marchetti, a World War II veteran who fought in the Battle of the Bulge. “I tell ‘em, ‘If I’m breading chicken, and not wearing an apron, I get stuff all over me. And if I’m wearing an apron, I still get it all over me. So why bother?’ ”

He was elated at the size of the crowd for Sunday’s grand opening.

“There must’ve been thousands who showed up,” he said. “Some people waited over an hour to get served. Can you imagine that? I wouldn’t wait an hour for the biggest lobster tail in the state of Maryland.”

-- Mike Klingaman