Mix Hong Kong flour and plain flour together in a bowl.

In another small bowl, add oil, golden syrup and lye water and mix everything well.

Slowly add the golden syrup mixture to the flour mixture and mix evenly until it forms a dough.

Cover the dough and set aside to rest for at least 1 hour.

Lightly toast melon seeds in the oven at 160°C for about 8 minutes. (optional step)

Mix red bean paste and melon seeds evenly together and set aside.

Weigh portions of dough of 50 g each.

For the red bean and melon seeds paste, weigh portions of 110 g each.

Make a depression in the red bean paste, insert a Ferrero Rocher, wrap and roll into a ball.

Roll a piece of dough flat and place the red bean paste ball in the center. Wrap the filling completely by slowly pushing the dough up the sides. Gently roll into a ball and flour it lightly.

Press the ball into a lightly floured mooncake mould. Press the mould plunger firmly (holding the base) and gently lift it up to release the mooncake.

For wooden or plastic mould, place the ball into the cavity, level it and press firmly. Gently knock the mould to release the mooncake.

Spray water all over the mooncakes to prevent the dough from cracking. (Edit: I have tested and found that it is better to leave out this step. You can prevent dough from cracking by lengthening cooling time to 10 to 15 minutes).

Bake at 180°C for 10 minutes.

Remove from the oven and cool for 5 minutes. (Edit: better to cool for about 10 to 15 minutes). Brush the mooncakes with egg wash.

Bake again for another 10 minutes until golden brown.

Place on a wire rack to cool completely before storing in airtight containers.