In a large bowl, mix together golden syrup, canola oil, and lye water until well combined. Gradually add cake flour, stirring gently until a smooth dough forms. Cover with plastic wrap and refrigerate for 40 minutes to chill.

While the dough chills, take the lotus paste and divide it into equal-sized balls. If using salted egg yolks, wrap a piece of lotus paste around each yolk, ensuring it’s fully enclosed.

Preheat your oven to 375°F. On a lightly floured surface, roll out the pastry dough to about 1/4 inch thick. Place a ball of filling in the center and fold the dough around it, pinching to seal. Mold the filled dough using a mooncake mold to create shapes.

Arrange the shaped mooncakes on a baking sheet lined with parchment paper. Brush the tops with egg wash. Bake for 12-15 minutes, or until the tops are golden brown and fragrant.

Once baked, allow the mooncakes to cool on a wire rack for at least an hour.