An Italian celebrity chef designs a fast-food burger.

one brisk autumn day in Milan, I walked into Il Marchesino—an upscale eatery inside La Scala opera house—carrying a brown-paper takeaway bag from McDonald’s. My lunchtime companion that day, the Italian chef Gualtiero Marchesi, was waiting at a small table against a wall. He was dressed in a well-tailored dark-blue suit, his silver hair swept back. On his lapel, he wore a coin-size replica of his most famous dish: a saffron risotto topped with a square leaf of edible gold.

Marchesi, a cherubic 81, managed to seem pleased, surprised, and embarrassed by my offering. With a giggle, he took the bag and set it down on the floor beside his chair. Marchesi is widely credited with elevating Italian food from home cooking to haute cuisine. He earned his first Michelin star in 1977 and eight years later became the first non-French chef to receive three. But I had come to see him about another, more recent, first. In 2011, Marchesi became the first celebrity chef to design a hamburger for McDonald’s—two of them, in fact, and a dessert to go with them. What I had brought in the brown-paper bag was Marchesi’s own creation.

Like the items on the menu at his restaurant, Marchesi’s burgers were designed with Italy’s culinary traditions in mind. He had topped one, called the Vivace, with ingredients typical of northern Italy: spinach, onions, bacon, and mayonnaise blended with whole-grain mustard. For the other, the Adagio, he had chosen flavors of Sicily. “Savor the creation of the maestro,” read the copy on the Adagio’s box. “An embrace of eggplant mousse harmonizes with tasty grated ricotta, fresh tomatoes, and beef. All enclosed in a soft bun with almonds. A melody of which you will never tire.” And then, in a script font, the McDonald’s signature: i’m lovin’ it.

The burgers, each of which costs about a euro more than a Big Mac, were a hit with Italians, and McDonald’s had recently extended a six-week nationwide run to two and half months. Still, interviewing Marchesi turned out to be a little like squeezing a wet bar of soap. It’s not that he didn’t want to talk about his collaboration with the fast-food giant. “I never had any doubts,” he told me. “If I had to worry about all the comments that have been made about me, I wouldn’t have arrived anywhere.” But it didn’t take much to send him off on a different track. So although he explained that he created his McDonald’s burgers to introduce young people to vegetables, I also got philosophical ruminations on the nature of cuisine (“Simplicity is a point of arrival, not a point of departure”) as well as complete non sequiturs (“We wage war to obtain peace. What sense does that make?”).

Marchesi had come to our appointment straight from the dentist, and after a few minutes he decided he needed to take a painkiller. He hadn’t planned to eat, but he didn’t want to swallow the pill on an empty stomach, and so he reached for the McDonald’s bag and pulled out its contents. The maître d’ materialized by the side of the table. Marchesi handed him the bag, but kept the boxes. “Leave it all here,” he said. “Let’s do a bit of advertising.” He opened the box containing the Vivace. “I’m Milanese,” he said. “So I like this one better, the one with the mayonnaise. It gives me the desire to eat one.” He looked up at the maître d’. “Can I?,” Marchesi asked. “At least try how it is?” He hunched his shoulders, darted his eyes theatrically, and gave the burger a big bite. “Buono,” he said. He turned to the table next to ours and added: “I’m reduced to eating my own hamburgers.”

To get the effect he was looking for, Marchesi had asked McDonald’s to sauté, rather than boil, the spinach for the Vivace. He added sunflower seeds to the bread, he said, as a play on textures, between their light crunch and the softness of the bun. “You know?” the chef said, looking up from his burger. “This is good. I’m going to eat another piece.” He turned to the other table. “You,” he said—“don’t look.” Ten minutes later, half the burger was gone and so was the entire dessert, a combination of two Italian classics, tiramisu and a sugary bread usually eaten at Christmas. He closed the boxes with the burgers inside and handed them to the maître d’. “Don’t throw them away,” he said. “I’ll eat them later.”