Start by whisking the eggs in a bowl until well-beaten. Gradually add in the warm water, soy sauce, and mirin (if using). In another bowl, combine the rice flour, all-purpose flour, baking powder, and dashi granules. Mix these dry ingredients into the wet mixture until all is well combined. Make sure to avoid lumps.

Preheat your Takoyaki pan over medium heat. Use a brush or paper towel to spread a thin layer of vegetable oil in each mold. It’s essential to coat each mold thoroughly. This will help them become golden brown and crisp.

Once the pan is adequately heated, pour the batter into each mold, filling them about halfway. The batter should sizzle lightly as you pour. Don't be shy to fill them up; they will expand during cooking!

Now it’s time to add the star of the show—octopus chunks! Place a small piece of boiled octopus and some of the diced shiitake mushrooms, ginger, and spring onions into each mold. The flavors will meld together beautifully.

Pour a little more batter over the top of the fillings, ensuring they are covered. This allows the Takoyaki balls to encapsulate everything inside, merging flavors as they cook.

After about 2-3 minutes, you’ll see bubbles forming on the surface. Now comes the fun part! Use a skewer or a fork to gently flip each Takoyaki ball in the mold. This might take a bit of practice, but don’t worry; even the imperfect ones taste amazing!

Keep cooking and flipping until the Takoyaki balls are a deep golden brown. This usually takes around 5-7 minutes in total. When they’re ready, they should be crispy on the outside and soft on the inside.

Carefully remove the Takoyaki balls from the pan and place them on a serving plate. The toppings can be dressed based on personal preference. A drizzle of Japanese mayonnaise, a sprinkle of bonito flakes, sesame seeds, aonori, and finally, a generous helping of Takoyaki sauce will make these balls utterly irresistible.