Leave the mould to set for 5 minutes then let it set completely in the freezer. Knock out the jelly mooncakes from the moulds. Keep the mooncakes chilled in the refrigerator before serving or packing them into boxes as gifts to relatives and friends. You can also use plastic mooncake moulds if they are available. They need to be chilled in the freezer before use as well.
Plastic moulds are convenient to use and yield excellent results.
Bring to a boil until sugar has dissolved. Add colouring and milk and blend well to mix. Pour into a shallow dish to set. Use a small watermelon scoop to carve out balls to be used as substitutes for egg yolk. Alternatively, you can pour mixture into small, round ice-cube moulds and knock out the 'yolks' when set.