When the Americans arrived in Japan after World War II, they set up headquarters in the New Grand Hotel in Yokohama. A crowd of hungry GIs had to be fed, so the Americans arrived with truckloads of spaghetti at the ready, which they dished out liberally. The Japanese cooks at the hotel took notice. When the GIs eventually departed, they left behind cases of spaghetti and ketchup in the hotel stockrooms. What to do? An inventive hotel chef created a dish with spaghetti, sausage, and ketchup (tomatoes were too expensive at the time), and dubbed it “Napolitan.” The people of Naples might not recognize this dish as their own, but, inexpensive and filling, it soon became a standard of school lunch menus across Japan. And what you eat as a kid, of course, is what you crave as an adult, and thus Napolitan happily entered the cuisine. If you’d like, you can substitute ham, bacon, or chicken for the sausage.

This recipe is excerpted from Japanese Soul Cooking: Ramen, Tonkatsu, Tempura, and More from The Streets and Kitchens of Tokyo and Beyond.