Whisk the Wet Base: In a large mixing bowl, vigorously whisk together the eggs, granulated sugar, and honey until well combined and slightly frothy. Stir in the mirin.
Dissolve the Leavening: In a separate small bowl, completely dissolve the 1 teaspoon of baking soda into the first 3 tablespoons of water. Pour this mixture into the egg base and whisk to combine.
Incorporate Flour Gently: Sift the flour into the bowl. Using a whisk, gently mix until the batter is smooth and no flour pockets remain. Do not overmix or overwork the batter, as this develops excess gluten and makes the pancakes tough.
Rest the Batter: Cover the bowl tightly with plastic wrap and let it rest at room temperature for 30 minutes. This resting period allows the flour to hydrate fully, creating a smoother texture and a uniform bake.
Adjust Consistency: After 30 minutes, unwrap the batter. Stir in the remaining 3 tablespoons of water to thin the batter to a smooth, pourable consistency.
Prep the Pan: Heat a high-quality non-stick frying pan or griddle over low heat. Lightly coat the surface with a small amount of neutral oil, then immediately use a paper towel to wipe away all excess visible oil. An oil-free surface texture is the secret to achieving that perfectly even, smooth golden-brown color without spotty patches.
Griddle the Pancakes: Ladle or drop the batter from a slight height directly onto the center of the pan to form a neat circle roughly 3 inches (8 cm) in diameter.
Watch for Bubbles: Cook on low heat for about 2 to 3 minutes. Flip the pancake when the surface is covered in tiny bubbles and the outer edges begin to look matte and dry.
Flash Cook the Second Side: Flip the pancake over carefully and cook the reverse side for just 15 to 30 seconds. Transfer immediately to a plate and cover with a clean, damp kitchen towel or plastic wrap to keep them soft and pliable. Repeat with the remaining batter.
Assemble and Seal: Take one pancake, place a generous dollop of sweet red bean paste right in the center, and top it with a second pancake. Gently press the edges together to seal the filling inside. Wrap the assembled dorayaki tightly in plastic wrap for a few minutes; this locks in the moisture and helps the edges hold their shape.