01 - Combine golden syrup, vegetable oil, and alkaline water in a mixing bowl. Whisk until thoroughly blended and emulsified.
02 - Add flour to the wet mixture. Stir with a spatula until a cohesive dough forms. Cover tightly with plastic wrap and let rest at room temperature for 2 hours to develop texture.
03 - Preheat oven to 350°F.
04 - Divide 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, rolling into smooth balls.
05 - Divide rested dough into 12 equal portions (approximately 0.7 oz each).
06 - Flatten each dough ball into a thin disc. Place one filling ball in the center and carefully wrap dough around, pinching edges to seal completely.
07 - Lightly dust mooncake mold with flour. Place filled ball inside and press firmly to imprint pattern. Release onto parchment-lined baking sheet.
08 - Continue shaping remaining dough and filling balls until all mooncakes are formed.
09 - Bake for 5 minutes to set the structure.
10 - Remove from oven. Brush tops lightly with egg yolk and milk mixture using a pastry brush.
11 - Return to oven and bake 15-20 minutes until golden brown.
12 - Cool completely on wire rack. Store in airtight container for 1-2 days before serving to allow pastry to soften and develop proper texture.