Tonka beans are very unusual little beans that grow primarily in the northern part of South America. They share a lot of similarities with vanilla beans, to the point where they are sometimes used as a vanilla substitute. They are black and wrinkly, about an inch long, and have a sweet flavour that is like a combination of vanilla, cloves and cinnamon with a nuttiness reminiscent of almonds. Really delicious and unusual.
Historically, tonka beans have been used in France for culinary purposes, and around the world in cosmetics, perfumes and tobaccos. The flavour of tonka beans is well-suited to cakes, puddings and other desserts (crème brulée!), and they are also lovely in coffee – just drop a single bean in with your grounds.