Combine water, egg, and dashi stock together in a bowl and mix well until frothy.
Get a strainer and sift the flour into a large mixing bowl, then pour 1/2 of the water mixture into it.
Whisk the dry flour and water mix thoroughly until they become viscous.
Pour the other half of the water mixture into the mixing bowl with the flour and water mix and blend well.
Use a kitchen brush and brush the takoyaki pan with cooking oil and then start heating it in the stove.
Pour the batter into each hole on the pan and make sure that you fill them halfway to the top and add the pickled ginger, tempura crisps, green onion, and diced octopus into the batter, then add more batter to seal it inside.
Allow the batter to cook for 2-3 minutes before flipping it over and let the other side cook too. Do remember to trim off the excess batter that overflowed when you poured them earlier. You can remix these batter into the next batch of takoyaki when you’ll pour them into the pan holes.
Do not stop flipping the takoyaki every minute or so until they become golden brown in color. The color change will indicate whether or not it is cooked.
When they’re ready, transfer them into a clean plate and coat them with the takoyaki sauce and Japanese mayonnaise, then drizzle them with bonito and aonori flakes before serving them to your guests.