The tonka bean, a wizened-looking South American seed, is beloved for its complex almond-vanilla scent, often appearing as an ingredient in perfumes. Outside the United States, it has also long been utilized by chefs, but studies have indicated that coumarin, a chemical compound in the plant, can cause liver damage in animals, and the Food and Drug Administration banned the bean in commercial foods in 1954. Now, with reports that the minuscule amounts used to impart big flavor are harmless (and the F.D.A. seemingly not particularly interested in enforcing the ban in recent years), tonka is showing up on dessert menus here. Thea Gould, 30, the pastry chef at the daytime luncheonette La Cantine and evening wine bar Sunsets in Bushwick, Brooklyn, was introduced to tonka after the restaurant’s owner received a jar from France, where it’s a widely used ingredient. Gould says the bean is an ideal stand-in for nuts — a common allergen — and infuses it into panna cotta, whipped cream and Pavlova. Ana Castro, 35, the chef and owner of the New Orleans seafood restaurant Acamaya, discovered tonka as a young line cook at Betony, the now-closed Midtown Manhattan restaurant. Entranced by the ingredient’s grassy, stone fruit-like notes, she’s used it to flavor a custardy corn nicuatole, steeped it into roasted candy squash purée and grated it fresh over a lush tres leches cake. And at the Musket Room in New York’s NoLIta, the pastry chef Camari Mick, 30, balances tonka’s richness with acidic citrus like satsuma and bergamot. Over the past year, she’s incorporated it into a silky lemon bavarois and a candy cap mushroom pot de crème and whipped it into ganache for a poached pear belle Hélène. “Some people ask our staff, ‘Isn’t tonka illegal?’” she says. Their answer: Our pastry chef’s got a guy. —