Honeycomb toffee

Honeycomb toffee, honeycomb candy, sponge toffee, cinder toffee, seafoam, or hokey pokey is a sugary toffee with a light, rigid, sponge-like texture. Its main ingredients are typically brown sugar (or corn syrup, molasses or golden syrup) and baking soda, sometimes with an acid such as vinegar. The baking soda and acid react to form carbon dioxide which is trapped in the highly viscous mixture. When acid is not used, thermal decomposition of the baking soda releases carbon dioxide. The sponge-like structure is formed while the sugar is liquid, then the toffee sets hard. The candy goes by a variety of names and regional variants.

Owing to its relatively simple recipe and quick preparation time, in some regions it is often made at home, and is a popular recipe for children. It is also made commercially and sold in small blocks, or covered in chocolate, a popular example being the Crunchie bar of Britain and Canada, or the Violet Crumble of Australia.

Regional names
Honeycomb toffee is known by a wide variety of names including:
 * cinder toffee in Britain
 * fairy food candy or angel food candy in Wisconsin
 * hokey pokey in New Zealand
 * honeycomb in South Africa, Australia, Britain, Ireland, Philippines, and Ohio, United States
 * old fashioned puff in Massachusetts
 * puff candy in Scotland
 * sponge candy in Milwaukee, Wisconsin, St. Paul, Minnesota, Northwest Pennsylvania, and Western New York
 * sponge toffee ("tire éponge") in Canada
 * Turkish honey ("törökméz") in Hungary

China
In China, it is called fēngwōtáng (蜂窩糖; "honeycomb candy"). It is said to be a popular type of confectionery enjoyed during childhood of the post-80s.

Hungary
In Hungary, it is known as törökméz (Turkish honey) and is commonly sold at town fairs.

Japan
The same confection is a traditional sweet in Japan known as karumeyaki (カルメ焼き), a portmanteau of the Portuguese word caramelo (caramel) and the Japanese word yaki (to bake), and thus can be roughly translated into English as "baked caramel" or '"grilled caramel." It is typically hand-made, and often sold by street vendors.

In Japan, raw egg whites are mixed with the baking soda to make the final product have a puffed up, dome shape.

South Korea
Dalgona is a Korean candy made with melted sugar and baking soda. It was a popular street snack in the 1970s and 1980s, and is still eaten as a retro food.

New Zealand
Honeycomb toffee is known as hokey pokey (especially in the Kiwi classic Hokey Pokey ice cream) in New Zealand. A very popular ice-cream flavour consisting of plain vanilla ice cream with small, solid lumps of honeycomb toffee is also known as hokey pokey. It is also used to make hokey pokey biscuits.

Taiwan
In Taiwan, it is called swollen sugar (膨糖, péngtáng or 椪糖, pèngtáng).