Crack the eggs in a small mixing bowl and add the water as well as the stock granules, then beat the mix manually or with an egg beater. Pour the egg-water-stock granules mixture into the flour, then add salt and mix well (with an egg beater or manually) until you’ve successfully created the batter.
Turn on the stove and place the takoyaki pan on top of it. Brush the individual half-sphere compartments with oil.
Two minutes into heating, pour the takoyaki batter into the concave semi-spherical molds. It’s okay if you accidentally make the batter in the molds spill over the brim as you can just gather them later when you’ll flip the batter over for the other side to be cooked.
Now, add the takoyaki fillings to the batter in the takoyaki pan. First, add 1 or 2 pieces of octopus to each ball, a bit of green onions in each ball, a bit of tempura, and 1 or 2 pieces of beni shoga.
Two to 3 minutes into cooking the takoyaki, when the bottom of the balls starts to harden, break apart the batter between the balls with your pick or skewers.
You may now flip it over in order for the other side to cook. Use a takoyaki pick when flipping the ball over in order to not ruin its spherical shape. You must turn the ball 90 degrees when flipping. If you can’t turn the takoyaki easily, it probably needs to cook for a bit longer.
When you poke the takoyaki to turn it over, some batter flows out and that's okay. Stuff it back in with the pick and add more batter if the ball loses its shape.
Let it sit in the pan for another 60 seconds before flipping it over. Turn the balls over repeatedly every 45-60 seconds for the next 5 minutes. The takoyaki balls should be easier to turn over once they’ve cooked through because the batter will no longer stick to the pan.
You will know when the takoyaki is done because it will have a light brown crispy texture on the outside and you can flip them easily in their holes as they no longer stick to the pan. The overall cook time is estimated to be 10 minutes per batch from the time you’ve placed them on the stove to the time you’ll take them out.
Place the hot takoyaki on a clean plate, then drizzle them with Japanese mayonnaise and takoyaki sauce. Sprinkle them with aonori and bonito flakes as well. Then serve them to your guests.