Taiyaki

In a large bowl, whisk together all-purpose flour, baking powder, and granulated sugar until well combined.

In a separate medium bowl, whisk the egg thoroughly, then add milk and water, mixing until the liquids are fully incorporated.

Gradually pour the wet ingredients into the dry ingredients, whisking continuously until a smooth batter forms. Be careful not to overmix. Allow the batter to rest at room temperature for 15 minutes.