These snow skin mooncakes with custard filling are perfect for Mid-Autumn Festival! Now only are they aesthetically pleasing, they're also filled with a fragrant custard and wrapped in pleasantly chewy snow skin!
Combine the milk powder, cornstarch, sugar and milk into a bowl and whisk until no more lumps are visible. Whisk in the eggs and melted butter until well combined.
Transfer the custard mix into a saucepan and heat over medium heat while constantly stirring. Once the custard starts to form a layer and thickens on the bottom of the pan, reduce the heat to low and keep constantly stirring until the entire custard is thick and kind of resembles scrambled eggs, about 5 minutes.
Once the custard has visibly thickened, cook for another 3-5 minutes until the custard is stiffer and dry enough to hold shape.
When the custard is stiff enough, transfer it into a fine mesh strainer. Push the custard through the strainer to remove any stubborn lumps and to make the custard smoother. Scale the custard into 30 gram balls and place it onto a plastic wrap covered plate. Wrap the custard refrigerated until needed.*If you are making the optional gooey matcha center, save 13 grams of custard filling for later. Then, divide the custard filling into 20 gram and 5 gram balls instead of 30 grams.*
For the optional gooey matcha center:
Scale out about 13 grams or about 1 Tablespoons of the prepared custard filling and transfer into a small bowl. Add the matcha powder and sugar and mix until everything is well combined. Stir in the melted butter until emulsified, then mix in the milk. Transfer the mix into a pipping bag and refrigerate until needed.
For the snow skin wrap:
In a microwavable bowl, whisk together the two types of rice flour, wheat starch, and sugar. While whisking, slowly pour in the milk and mix until no lumps remain. Add the condensed milk and oil, then whisk to combine.*If needed, you can strain the batter to push out any stubborn lumps of flour.*
Cover the bowl with plastic wrap and poke a few holes in the wrap. Microwave the batter for about 2 to 2½ minutes on high, or until the batter is cooked through and no more liquid batter is visible. *You can also steam the batter on medium high heat for about 15 to 20 minutes or until the dough is cooked.*
Cut the dough into pieces with a rubber spatula to cool it faster. Once the dough is at a comfortable temperature for handling, knead the dough into a smooth ball with gloved hands.
Divide the dough into 20 gram pieces and place them on either plastic wrapped surface or parchment lined sheet pan. Keep the dough covered until needed.*If making marbled snow skin, divide the white snow skin dough into 15 gram pieces.*
Optional for a marbled look:Scale out 100 grams of the dough and add about ½-1 teaspoon of matcha powder to the dough (depending on how green you'd like the dough). Knead the matcha powder into the dough until the powder is evenly spread out. Scale the dough into 5 gram pieces and keep them with the white snow skin doughs.
Snow skin mooncake assembly:
With gloves on, roll the snow skin dough into a ball, then flatten it evenly into a circle between your palms to about 3 inches wide. Place the custard filling in the center of the wrap and gently work the snow skin around the filling, then pinch together the edges to seal the mooncake. Repeat with all filling and wraps while keeping everything covered to prevent drying out.
For gooey matcha center:Make an indention in the 20 gram ball of custard filling and try to mold the custard into a hallow ball with ¼ inch wall. Try to keep the opening as small as possible. Pipe in the prepared matcha filling just under the rim. Gently flatten the 5 gram ball of custard filling and patch up the opening. Smooth the patched area and gently roll the custard into a ball.For the marbled snow skin:Twist together the 15 grams white and 5 grams green snow skin dough, then roll it back into a ball. Flatten the dough evenly with your palms, into 3 inch wide circles. Wrap the custard filling gently and seal up the opening. Repeat with remaining dough and filling while keeping everything covered.
Fit the mooncake mold with your desired pattern. Working with one ball of mooncake at a time, dust the mooncake with a small amount of cornstarch and dust off the excess. Gently roll the mooncake to into a cylinder so that it'll fit in the mooncake mold and insert it into the mold.Gently but firmly, press down on the mold level and hold for 5-10 seconds to form the pattern. Release the level and the mooncake should come out of the mold with no problems. If the mooncake gets stuck, just lift the mold off the surface and push on the lever. Cover the mooncake and repeat with the rest.
Enjoy the snow skin mooncakes as is or chill for 1-2 hours for better flavor! Make sure to keep them in airtight containers.
Snow skin mooncakes are best enjoyed the day of. If you have leftovers, keep them in airtight containers and refrigerate for up to 3 days. The longer they are kept refrigerated, the more the snow skin's texture will lose integrity. So enjoy as soon as possible!
You can also freeze the snow skin mooncakes, but the snow skin will behave the same as when they mooncakes are refrigerated. If freezing these mooncakes, keep them in airtight containers. Thaw them in the fridge or at room temperature before enjoying.