01 - In a mixing bowl, combine golden syrup, vegetable oil, and alkaline water. Whisk thoroughly until the mixture is fully emulsified and homogeneous.
02 - Add flour to the wet mixture and stir until a smooth dough forms. Cover tightly with plastic wrap and let rest at room temperature for 2 hours to allow the gluten to relax.
03 - Preheat oven to 350°F.
04 - Divide the lotus seed paste into 12 equal portions, approximately 1.4 oz each. If using salted egg yolks, encase each yolk within a portion of paste and roll into smooth balls.
05 - Divide the rested dough into 12 equal portions, approximately 0.7 oz each.
06 - Flatten each dough ball into a thin disc. Place a filling ball in the center and carefully wrap the dough around it, pinching edges to seal completely.
07 - Lightly dust the mooncake mold with flour. Place each filled ball into the mold and press firmly to imprint the pattern. Release onto a parchment-lined baking sheet.
08 - Bake for 5 minutes to set the structure.
09 - Remove from oven and brush lightly with egg wash mixture, being careful not to flood the imprinted designs.
10 - Return to oven and bake for an additional 15-20 minutes, or until the pastry develops a rich golden-brown color.
11 - Cool completely on the baking sheet. Transfer to an airtight container and store for 1-2 days before serving to allow the pastry to soften and develop the traditional texture.