Begin by whisking eggs and sugar in a large mixing bowl.
Add honey and whole milk to the mixture and combine well. Sift all-purpose flour and baking powder together, and then add it to the egg mixture.
Further, mix well until all ingredients are well combined. Then rest the batter for at least 15 minutes to allow the gluten to relax.
While the batter is resting, take 2 tablespoons of sweet red bean paste. Then shape it into a round disk that will fit in the centre of each pancake.
Heat up the pan over low heat to 350ºF (175ºC) as high heat can cause uneven heating. Use a small piece of paper towel to apply a thin layer of vegetable oil to the pan. Wipe off the excess oil with a clean paper towel.
In addition, heat the pan first. Then pour the batter into a liquid measuring cup for easy pouring, and then fill the pan halfway with batter. Cook for 2 minutes, then add the red bean paste and set the timer for 3 minutes. After 1 minute, pour batter into the empty third of the pan and cook for the remaining 2 minutes.
Using a small metal spatula or skewer, pick up two pancakes with the filling. Then place them on top of the pancakes without filling.
Press down and cook for another 2 minutes. Loosen the edges of the pancakes and remove them from the pan. Lastly, cool the Imagawayaki on a wire rack, and repeat the process until all batter gets finished.