Heat the takoyaki pan to 400 ºF (200 ºC) over medium heat.
Using a brush, generously oil the takoyaki pan (both the holes and connecting flat areas).
When you see smoke coming from the pan, pour the batter to fill the holes. It’s okay for the batter to slightly overflow the holes. Usually as you add ingredients to the batter it will overflow.
Add 1-3 octopus pieces in each hole depending on its size and sprinkle katsuobushi powder you ground earlier on top.
Then sprinkle tenkasu, green onion, and pickled red ginger.
After 3 minutes or so, when the bottom of the balls has hardened slightly, break the connected batter between each ball with skewers. Then turn each piece a 90 degree, stuffing in the edges as you are turning. The batter will flow out from the inside of each takoyaki ball and creates the other side of the takoyaki ball.
After you finish flipping, set timer for 4 minutes. Keep turning constantly so each piece will have nice round shape.
Transfer takoyaki balls onto a plate and pour takoyaki sauce, mayonnaise. Finish off with sprinkling katsuobushi and dried green seaweed.
It's gonna be hot, but it's gonna be good.
DONE!