When Christianne Muusers, a Dutch culinary historian, was researching World War II-era cookery, one story stood out. Her elderly neighbor recounted growing up in Nazi-occupied Rotterdam, a city that was all but reduced to rubble by German aerial bombings in 1940 and then by Allied bombings in 1943. By 1944, when he was nine years old, there was only one thing left to eat: tulip bulb soup. “His father had been eating almost nothing but tulip bulbs,” says Muusers, who specializes in recreating Medieval peacock pie and other long-lost recipes….