Sweet Red Bean Paste Filled Fish Pastry

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

In a separate medium bowl, whisk the milk and egg until thoroughly mixed. Gradually add the melted butter to the wet ingredients, whisking constantly until smooth.

Pour the wet ingredients into the dry ingredients. Whisk until just combined; do not overmix, as a few small lumps are acceptable. Let the batter rest for 10 minutes to allow the flour to hydrate.

Heat a bungeoppang pan (fish-shaped waffle iron) over medium-low heat. Lightly brush the insides of the fish molds with vegetable oil.

Pour about 1-2 tablespoons of batter into each fish mold, filling it approximately halfway. Immediately place a generous spoonful of sweet red bean paste in the center of each mold, then cover with another 1-2 tablespoons of batter.

Close the pan firmly and flip it over. Cook for 3-4 minutes on each side, flipping the pan occasionally, until the pastries are golden brown and crispy.

Carefully open the pan and remove the bungeoppang. Serve immediately while warm for the best taste and texture.