In a large bowl whisk together the dry ingredients: Cake Flour, Baking Powder, Sugar and a pinch of Salt.
In a separate bowl lightly beat the Eggs, then add the Milk and Neutral Oil and whisk until combined.
Pour the wet mixture into the dry ingredients and stir gently until just combined — a few small lumps are fine and help keep the cakes tender.
Let the batter rest at room temperature for 15–30 minutes to hydrate the flour and produce a lighter texture.
Heat an imagawayaki pan or a nonstick griddle over medium–low heat; lightly oil each cavity or the surface so the cakes release easily.
When the pan is hot, pour a small ladleful of batter into each cavity to form a base, spoon a portion of Tsubuan into the center, then cover with a little more batter so the filling is enclosed.
Close the pan or cover with a lid and cook for about 2–3 minutes, then flip the mold (or flip each cake) and cook another 2–3 minutes until the cakes are puffed and golden brown.
Transfer the finished imagawayaki to a wire rack and let them cool for a minute or two — they are best served warm so the tsubuan remains soft and slightly molten.
If you don’t have a specialized pan, you can use a small nonstick pancake griddle or a muffin tin; adjust portion size and increase cook time slightly until fully cooked through.
