Crack the Salted Duck Egg (5) and remove the egg white part. Gently rinse each yolk under the water to completely remove all the white.
Prepare all ingredients needed to make these Shanghai mooncakes.
Preheat oven to 180 degrees C (350 degrees F).
Bake Salted Duck Egg Yolks for 10 minutes. Then lightly toast Melon Seeds (25 gram). Set them aside to cool before use.
Put Margarine (105 gram) and Powdered Confectioners Sugar (55 gram) in a mixing bowl of a stand mixer. Cream until well combined. Then add in the Egg (3) Yolks one at a time. Mix to combine well after each addition. Then, mix the batter with Evaporated Milk (1 1/2 tablespoon).
Slowly add in the sieved All-Purpose Flour (220 gram) and Custard Powder (1 1/2 tablespoon) until a soft dough is formed. Cover with cling wrap and rest the soft dough for 30 minutes.
After 30 minutes, divide the rested soft dough into 5 equal pieces, 80g each. Meanwhile prepare mooncake filling.
First knead toasted melon and White Sesame Seeds (2 1/2 teaspoon) into the Lotus Seed Paste (500 gram) till well combined. Then, form the lotus paste into a log and divide into 5 equal pieces, 105g each. Wrap each piece of lotus paste with one egg yolk (15g) and form into ball. You should have 5 lotus paste balls, each weighing 120g.
To assemble the mooncakes, first flatten the soft pastry dough and wrap around the lotus paste ball. Gently push, press and squeeze the dough, holding the ball securely in your palm, until the dough skin gradually covers the lotus paste ball. Roll into a ball. Repeat this step to finish the remaining dough skin and lotus paste balls.
Next, mould the mooncake. Dust a little flour on the mooncake mould. Place the stuffed round mooncake into the mould. Turn it UPRIGHT on a smooth surface. Then press the plunger down until you feel resistance. Lift the mooncake mould off the surface and use the plunger to push the mooncake out.
Repeat the same with the rest of the wrapped lotus paste balls. Then arrange the mooncakes onto a baking tray. Lightly wash with Egg (1) on the surface of each mooncake.
Meanwhile, preheat oven to 190 degree C (375 degrees F). Place mooncakes into the preheated oven to bake for 20 to 25 minutes, or until golden brown in colour. Then remove and transfer the baked mooncakes to cool completely on wire rack.
These mooncakes are best served after 2 to 3 days to allow the pastry to absorb some oil from the filling. Hence the skin will turn soft and has a crisp but crumbly texture.
At this point, cut into small wedges and enjoy!