Unlike other legumes with the "bean" suffix, the tonka doesn't much resemble what you find in your chili — it looks more like an elongated raisin or a hard, skinny date. It also doesn't taste like your run-of-the-mill black or pinto bean, but instead follows the sweet path of vanilla, with a slight fruity spice and sometimes an almond-caramel essence on the finish. It's used mainly in desserts, and surprisingly, it's illegal to sell here in the United States. Intrigued? We thought so. This little legume not only offers a beguiling taste, but its history is packed with mystery as well.
Where they're from: These little black pods come from the flowering cumaru (also spelled kumaru) tree, a plant found in Central and South American that belongs to the pea family. Like many foods that showcase a deep and unique flavor, the tonka bean has a bit of mysticism surrounding it. For centuries, pagans and followers of the occult have believed this one-inch legume can help cure depression and, if a ritual is performed properly, grant you your deepest wish. However, these magical properties are not why tonkas are banned in the States. Turns out they contain coumarin, a naturally occurring chemical that can cause liver problems when taken in high doses. Specifically, more than you can probably eat — or would want to eat — at a time. Sadly, because of this, the legumes have been on the FDA's no-no list since 1954, which is ironic given that coumarin has also been found in non-illegal foods, including cinnamon, lavender and licorice. Of course, like many things in the States, you can find them at some specialty shops (like Kalustyans in New York City) and online.
When they're in season: Because you don't buy these fresh, or legally at all in the States, consumers don't have to follow the season of the tonka, which is June and July in the major growing areas of Venezuela, Colombia and Brazil. Here in the U.S., we see them dried and treated as any other bean.
What to look for: The majority of tonka beans are about one inch long, dark brown to black, and shriveled up like a piece of dried fruit. They shouldn't look ashy or crumbly, and if the opportunity arises, buy ones that are firm and dark.
How to store them: Like other beans, you want to keep tonkas in cool, dry, dark places in an airtight container. They should last months, even years this way, though over time the flavor will mellow out, so it's best not to store them for too long.
How to prepare them: You will often see the tonka delicately shaved over dishes, a preparation that releases its pungent aroma and subtle flavor. Recently at a special dinner at New York City's Chefs Club, Minnesota-based chef Erik Anderson, formerly of the Catbird Seat in Nashville, surprised diners by incorporating tonka beans in a savory dish. "I use them for infusing stuff like cream," he says, describing a porridge he made from Danish rye bread, hickory nuts and truffle that was cooked in said cream. "Tonka beans are fantastic. You can use them in sweet or savory applications, and the flavor is like a cross between almond and vanilla."
Anderson has also used the legume to flavor ice cream and as a component of a gin fizz, and he once did a burned-sugar pudding using tonkas instead of the traditional vanilla. As far as whether these beans can replace vanilla in any recipe, the chef says, "You can try it. I don't see why it would hurt it."
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