South Korea is proud of its spicy food. It is one of very few cold weather countries to embrace the chili pepper. Foreigners are often incredulously asked, "You can eat that?" when tucking into a bowl of kimchi jjigae or a plate of fire chicken.

But the hottest food in South Korea isn't kimchi stew, fire chicken or any of the country's other gastronomical blast furnaces. In a small alleyway in Seoul's theater district, an Iranian restaurant, Persian Palace, serves food so hot it has sent patrons to the hospital.

A hobby takes flight

Shapour Nasrollahi, the owner of Persian Palace, is that rare but increasingly common creature, an immigrant to South Korea, a naturalized Korean citizen with no Korean ancestry, only a passion for Korean culture, language and society. Born and raised in Iran, he served as a medic in the Iran-Iraq War, and was wounded in the leg during battle. In 1990 he moved to Japan, in an attempt to emigrate to Canada to attend medical school.

But after visiting a friend in Seoul, he decided to stay and learn the Korean language -- he was fascinated with "Hangul," Korea's ultra-scientific writing system, having studied in linguistics departments around the world. He learned the language and enrolled in college, obtaining degrees in medicine and psychology. He figured he would eventually go to work at a large South Korean company, but in the meantime, he'd like a break -- he figured he'd cook.

"Cooking was my hobby all my life," he says. "I thought just to have a six-month to one-year break, and I'll make one small shop to do what I want, cooking."

Spicy to ultra-spicy curries

Shapour's spicy to ultra-spicy curries became legend, and soon his hard-to-find shop became extremely popular. He expanded and bought out the whole building, built a pub downstairs, and hasn't closed for a single day in 10 years. "I wanted to do this business for six months," Shapour says. "Six months became almost 15 years."

So how spicy is it? Shapour has engineered a number system so people can decide how hot they want their food. The lowest level is 2.0, which he says is comparable to kimchi. Two-point-five is like a "Mexican chili" pepper, and from there it gets stronger and stronger. If you want 5.0, he takes your blood pressure first, to decide if it's a good idea or not. After 6.0, a customer has to sign a waiver, promising that "if anything happens to him, he's responsible."

Off-the-scale heat

"Look," Shapour says, "Level 5, sometimes they order, but I never, ever saw a person eat all of Level 5 and go out nicely. Do you know what I mean? They fall down."

No one has ever eaten a Level 10, though one patron once ordered one.

"Three years ago, one Korean guy he came here, it was Christmas Eve," Shapour says. "He was almost 100% drunk, he asked me for Level 10. I made Level 7 for him, because he made trouble here. I gave him Level 7. I told him, ‘This is Level 10.'" Shapour laughs. "As I remember, two spoons he ate, and he never came back here again. I don't know what's happened to him."

The curries are rated for spiciness from 1 to 10 - and nobody has ever eaten a 10. Photo: Shutterstock

Shapour uses a mix of 24 spices to make his curries, eight of which are spicy. Chief among those is the Sahara pepper, a small, round and wrinkly red pepper, which Shapour says is off the Scoville scale in hotness. He makes a masala out of it, as well as inserting it directly into the curries. "With bare hands, if you touch it, and then you touch your eyes, God [help] you."

A complex mix of flavors

Shapour doesn't practice medicine anymore, but he still sees himself as something of a doctor, using traditional ingredients to heal. For example, he says Iranians view cumin as good for digestion and post-pregnancy, cinnamon as a tonic for headaches and to warm you up, and cardamom as good for brain disease and to control anger.

But is the food really that spicy? Our party ordered four curries at four different heats: a vegetable curry (2.5), dal (3.0), chicken (3.5), and turkey (4.0), all eaten with plain nan.

Shapour's reputation as a cook stands up. A complex mix of flavors -- cumin, coriander, curry and more -- rise through the heat. But they are extremely hot, the last two painfully so, by far the hottest food we had ever eaten in South Korea. The final two curries were left unfinished.

And when one of us complained of indigestion caused by the fire, Shapour immediately provided a glass of Alka-Seltzer -- he keeps a stock of it behind the cash register for situations just like these.