Adzuki Mooncake

In a small saucepan, gently warm the golden syrup and 3 tablespoons of peanut oil over low heat until the syrup is easily stirred, about 3 minutes. Meanwhile, in a mixing bowl, whisk together the cake flour, baking soda, and salt. Incorporate the warmed golden syrup mixture until a smooth dough forms. Wrap the dough tightly in plastic wrap and refrigerate for at least 4 hours.

Rinse the adzuki beans and place them in a large saucepan with 4 cups of water. Bring to a boil over high heat, then reduce heat to medium-low, cover, and simmer until the beans are tender, approximately 1 hour. Drain the beans thoroughly and allow them to cool for about 10 minutes. Puree the cooled beans in a blender or food processor until smooth.

Heat 1/4 cup of peanut oil in the same saucepan over medium heat. Add the pureed adzuki beans and sugar. Cook, stirring continuously, until the bean paste thickens and clings to your spoon, about 10 to 20 minutes. Stir in the wheat starch until well combined. Transfer the bean paste to a mixing bowl and chill in the refrigerator until completely cold.

Preheat your oven to 375 degrees F (190 degrees C). Lightly grease a baking sheet.

Divide both the chilled dough and the chilled adzuki bean filling into 8 equal portions. Roll each portion into a ball. Flatten a dough ball between your palms to create a circle large enough to encase a filling ball. Place a ball of filling in the center of the dough circle, carefully wrap the pastry around the filling, and pinch the edges to seal. Gently roll the mooncakes in all-purpose flour, shaking off any excess. Place the mooncakes seam-side-down on the prepared baking sheet and gently press to flatten slightly.

Lightly mist the mooncakes with water using a spray bottle. Bake in the preheated oven for 8 minutes. Remove the mooncakes from the oven and reduce the oven temperature to 300 degrees F (150 degrees C).

Brush the tops of the mooncakes with the beaten egg yolk, applying a slightly heavier coat to the tops than the sides. Return the mooncakes to the oven and bake until they are golden brown, about 15 minutes more. Allow the mooncakes to cool completely before serving.