In the bowl of a stand mixer fitted with a paddle, combine the flour with the custard powder. In a medium, high-sided saucepan, bring the honey, molasses and salt to a boil. Meanwhile, in a small bowl, stir the baking soda with 1⁄4 cup water.
Add the baking soda solution to the boiling syrup and cook, stirring, for 3 seconds (the syrup will bubble up). Remove the syrup from the heat and pour into the flour along with the peanut oil and turn the mixer on medium speed. Mix the dough until smooth, about 90 seconds, and then form into a ball and wrap in plastic wrap. Let the dough rest at room temperature for at least 2 hours.
Divide the dough into 2-oz. balls and place on a parchment paper-lined baking sheet. Wrap the baking sheet in plastic and let stand at room temperature until ready to use. *If making the dough ahead, refrigerate the dough, and allow it to return to room temperature before proceeding.
Heat the oven to 375°. In the bowl of a stand mixer fitted with a paddle, beat the lotus seed paste with the almond paste, oil, salt, and zest on medium-high speed until smooth. Reduce the mixer speed to low and add the apricots, cherries, and ginger, followed by the almonds and pecans. Add the chocolates, and beat until just combined. Divide the filling into about twenty-eight 3 1⁄2-oz. pieces, and roll each piece into a ball.
Using a rolling pin, flatten each ball of dough into a 5-inch circle, about 1⁄4-inch thick. Place a ball of filling in the middle of each dough circle and wrap the dough around the filling, sealing it in completely and smoothing out the surface. Place each dough-wrapped ball into the lightly floured cavity of a mooncake paddle (amazon.com) and press to fill the mold. Bang the mooncake paddle on each side against a work surface to loosen the mooncake, and then turn the paddle so the cavity is facing down and bang the paddle to release the mooncake, allowing it to fall onto the work surface. Arrange the molded mooncakes on parchment paper-lined baking sheets, spaced 2 inches apart and spray lightly with water.
Bake the mooncakes for 10 minutes and then remove from the oven and lightly brush each with egg wash. Reduce the oven temperature to 350° and bake until golden brown and warmed in the center, 5 minutes more. Remove the mooncakes from the oven and transfer to a rack to cool completely. Ideally, allow the mooncakes to sit at room temperature, sealed in an airtight container, for 2 days to allow to soften before eating.