Combine lychee syrup, sugar, agar-agar powder, instant jelly and pandan leaf in a saucepan and bring to a boil.
Add in soya bean milk and allow the mixture to come to a boil. Remove from heat, add in milk, essence and chopped lychees. Stir well to cool slightly. Pour into well-chilled mooncake moulds up to the brim. Leave aside to set then set them completely (until firm) in the freezer. Knock out gently. Keep the jelly mooncakes well-chilled in the refrigerator until serving time.