Mr. Lowe, who opened Lyle’s and, recently, Flor, has made a mission of uncovering forgotten British ingredients like Alexanders (a variant of parsley), beremeal (an ancient strain of barley, grown in Scotland) and Stichelton, a veined blue cheese made from raw milk. (Stilton, England’s famous blue, is now made from pasteurized milk.)
Ms. Travers no longer restricts herself to local ingredients. “I was always trying to sneak pineapple onto the menu” at St. John, she said, by arguing that Victorian-era aristocrats grew them in hothouses. But she does go to the source for ingredients, driving to Italy to pick out Amalfi lemons and to France for ripe apricots for her small-batch ice creams.
Whether she will be able to keep road-tripping for fruit now that Britain has left the European Union is in question. And the national debate over Brexit has highlighted thornier questions — about what and who belongs inside British borders — that extend into the food world and, by extension, the Henderson Triangle.
“I don’t think they set out to romanticize British food,” said Anna Sulan Masing, who writes about food and identity and is co-host of a podcast called “Voices at the Table.” “But there is this magical narrative with rose-colored glasses about what Britain used to be.”
At St. John, that narrative does not include plantains from the Caribbean, pomegranates from the Middle East or pasta, for that matter. “They have their core ingredients,” Mr. Bowien said admiringly. “They’ve never wanted to take their ox head and put it into tacos, or start nixtamalizing corn.”
Still, the Hendersons are trying to move the needle on diversity among their employees. Like most restaurant kitchens, St. John’s have long been overwhelmingly male. The Rochelle Canteens are largely staffed by women, but there has not yet been a female head chef at a St. John restaurant.
The current chef at St. John Bread and Wine, Farokh Talati, is the son of Parsi immigrants from India, and the first person of color to head a St. John kitchen.