01 - In a bowl, combine golden syrup, vegetable oil, and alkaline water. Mix until well blended and emulsified.
02 - Add flour to the wet mixture. Stir until a dough forms. Cover with plastic wrap and let rest for 2 hours at room temperature.
03 - Preheat oven to 350°F.
04 - Divide the lotus seed paste into 12 portions (1.4 oz each). If using, wrap each salted egg yolk inside a portion of paste and roll into a smooth ball.
05 - Divide the rested dough into 12 portions (approximately 0.7 oz each).
06 - Flatten each dough ball into a disc. Place a filling ball in the center and carefully wrap the dough around, pinching edges to seal completely.
07 - Lightly dust a mooncake mold with flour. Place the filled ball inside and gently press to shape. Release onto a parchment-lined baking tray.
08 - Repeat with remaining dough and filling portions until all mooncakes are formed.
09 - Bake for 5 minutes, then remove from oven.
10 - Brush mooncakes lightly with egg wash mixture.
11 - Return to oven and bake another 15-20 minutes, or until golden brown.
12 - Cool completely on wire rack. Store in an airtight container for 1-2 days to allow the pastry to soften before serving.