• Gather all the ingredients.
  
  

To Prepare the Filling

• Grind ¼ cup katsuobushi (dried bonito flakes) into a fine powder. Set aside to use during cooking.
  
• Cut 2 green onions/scallions into thin slices and mince 1 Tbsp pickled red ginger (beni shoga or kizami beni shoga).
  
• Cut 4.2 oz octopus sashimi (boiled octopus) into bite-sized pieces about ½ inch (1.3 cm); I use the rangiri cutting technique. Tip: Cut it into smaller pieces so it's easier to chew, especially for kids.
  

To Make the Batter

• Combine 1 cup all-purpose flour (plain flour), 2 tsp baking powder, and ½ tsp Diamond Crystal kosher salt in a large mixing bowl. Whisk it all together.
  
• Add 2 large eggs (50 g each w/o shell), 1 tsp soy sauce, and 1½ cups dashi (Japanese soup stock) to the bowl.
  
• Whisk until well blended. Transfer it to a handled measuring cup or any pitcher with a spout for easy pouring.
  

To Cook the Takoyaki

• Heat the takoyaki pan to 400ºF (200ºC) over medium heat. Use a brush to generously grease the rounded chambers and flat top surface with 2 Tbsp neutral oil. When the oil starts to smoke, pour the batter to fill the chambers. It’s okay to slightly overfill the cavities. In the next steps, the batter will likely overflow as you add more ingredients to it.
  
• Add 1–3 octopus pieces, depending on their size, to each chamber and sprinkle the ground katsuobushi powder on top.
  
• Sprinkle ⅓ cup tenkasu/agedama (tempura scraps), the green onion slices, and the chopped pickled red ginger on top. After 3 minutes or so, when the batter on the bottom has set and is slightly crisp, use skewers to break the connected batter on top between the chambers. Rotate each piece 90 degrees (a quarter turn) toward the bottom of the pan. Stuff the connected dough back into the ball as you turn; the uncooked batter will flow out from inside to create another side of the ball. After you finish turning them, set a timer for 4 minutes.
  
• After 4 minutes, rotate them again, starting with the first ball. Turn each takoyaki another 90 degrees toward the bottom of the pan so the remaining uncooked batter pours out into the chamber to complete the ball shape. Home takoyaki griddles don‘t distribute heat evenly, so it’s a good idea to swap the balls around to different chambers so they brown evenly. After turning and cooking for another 4 minutes, they are done.
  

To Serve

• Transfer them onto a plate and drizzle with ½ cup takoyaki sauce and Japanese Kewpie mayonnaise. Sprinkle with katsuobushi (dried bonito flakes) and aonori (dried green laver seaweed) and serve with a side of pickled red ginger (beni shoga or kizami beni shoga). Serve immediately. (But, be careful—they‘re VERY hot inside!)
  

To Store

• You can keep the leftovers in an airtight container and store in the refrigerator for 3 days or in the freezer for 2–3 weeks.