|Here tenkasu is sprinkled into takoyaki|
You buy them in a small packages about 5x8 inches (usually clear plastic, bag-type, so you can see what's inside)
Tenkasu is made by pouring Tempura batter into hot oil. The batter separates into droplets which puff in the oil. It is then scooped off, drained and packaged.
Unlike rice bubbles, Tenkasu holds it's shape and stays crisp even when wet.
It is added to Takoyaki to add volume which won't shrink as the takoyaki cools. This allows for perfectly round takoyaki.
It is sometimes added to Okonomiyaki.