Week two of “The Great British Bake Off” put the focus on biscuits as the bakers whipped up a dozen Hobnobs and showstopping memento time capsules. Of course, bakers also had to get creative with their flavors. One, in particular, incorporated a rather unique ingredient — tonka, which has been referred to as vanilla’s “cousin.”
In the signature challenge, Aaron Mountford-Myles, a London-based baker, made slice-and-bake cookies inspired by his best friend’s daughter, Winnie. The aptly named “Mini Winnies,” which look endearingly cartoonish, featured a tonka and malted milk biscuit dipped in milk chocolate. They later received compliments from Prue Leith, who praised the intricate “layers of flavor.” Paul Hollywood also agreed that they were “delicious.”
There’s not much explanation — or demonstration — as to how Aaron actually flavored his biscuits. But when it comes to cooking with tonka beans, the most common technique is to infuse them in liquid, namely milk, cream, custard or alcohol. The individual beans, which resemble shrunken dates due to their wrinkly dark exterior, can also be microplaned to create a fine powder, according to a guide from Great British Chefs. “The tonka bean powder can be used like any other dry spice, for example it might be mixed with white flour to make a tonka-flavoured bread, mixed with icing sugar to make a tonka-flavoured macaroon, or mixed with all spice to flavour a bread and butter pudding,” the guide explained.
Tonka is described as tasting like vanilla — warm, floral and sweet — but with a more pronounced “woodsy” profile. As written by Claire Dinhut, tonka “has a sweetness to it that resembles grassy, hay-like, fresh vanilla. However, tonka beans also give off a slightly warming and spicy aftertaste of cinnamon, clove and nutmeg.” Edd Kimber, who writes the food blog The Boy Who Bakes, said tonka “has a unique flavour, a mash up of vanilla and spice. Its a strong flavour and needs to be used sparingly but it can really elevate a dish and make it wonderfully special.” Great British Chefs specified that tonka’s “most distinctive feature” is their “enormous potency — heady vanilla flavours, with oily clove aromas, and perfumed magnolia, sandalwood notes.”
The tonka bean’s robust scent comes from the presence of coumarin, a naturally occurring organic compound that’s also found in Cassia cinnamon and some licorice roots. The beans themselves grow on the Dipteryx odorata tree, commonly known as the Cumaru tree, that’s native to Northern South America.
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A superstar in French cuisine, tonka has also made its fair share of cameos on “Bake Off,” notably in an apricot compote and a mascarpone cream paired with a ginger, fig and honey pudding. Shockingly, however, tonka beans are illegal in the United States. In 1954, the Food and Drug Administration (FDA) banned the sale and use of tonka beans in commercial foods due to its high coumarin content, which can cause liver damage. That being said, one tonka bean won’t do any damage. You’d need to eat 30 whole beans for the coumarin levels to cause liver failure.
Despite their lack of abundance in the States, tonka beans are reportedly incredibly easy to obtain. That’s according to The Takeout, which reported that tonka can be ordered online, even on Amazon. Several specialty spice shops around New York City also sell tonka.
If you’re looking for a substitute that’s 100% legal, vanilla extract and almond extract are your closest options. You can also try spicing up your vanilla, per Redditor u/shazeaa: “Vanilla bean and some nutmeg to bring on the richness!” Or you can live vicariously through the bakers on “Bake Off” — whatever satisfies your culinary endeavors.