Put lotus seeds into a large mixing bowl. Add alkaline water and steep for 5-10 minutes. Pour boiling water over the seeds then cover and soak for 10 minutes.
Drain the water from the seeds then add cold water. Next, completely remove the skins from the seeds by rubbing them off. If whole lotus seeds are used, remove the green centres then boil seeds in water until soft and tender.
Blend the cooked lotus seeds into a fine paste in an electric blender or food processor.
Heat up a wok and melt half the sugar until it turns lightly golden.
Add lotus seed paste. Cook, stirring all the time until the lotus seed paste thickens. Add in the remaining sugar and pour in the oil a little at a time. Continue to cook until it is thick. Stir in maltose. Use a wooden spatula to stir until the paste leaves the sides of the wok.