To make syrup, cook brown sugar with water until completely dissolved, remove from heat and leave to cool.
Mix all ingredients A, rest for 1-2 hours for fermentation, set aside.
Whisk eggs and sugar of the ingredients B until light and vreamy with mixer, add in plain flour, syrup, melted butter and dark soya sauce and mix well.
Add in ingredients C and ingredients A mixture, stir until becomes smooth batter.
Lay a piece of greaseproof paper in a steaming basket, pour in batter mixture, sprinkle with melon seeds for topping.
Steam in a preheated steamer at high heat for 35-40 mins or until cooked through. Remove.