In a medium pot, bring the water to boil in high heat.
Meanwhile, put the ginger slices on the chopping board. Hit the ginger with the side of a knife to release the ginger juice and flavor.
Once the water is boiled, put in half of sugar and the ginger slices. When the sugar has melted, taste to try. Adjust the sweetness to your likeness.
Take out the glutinous rice balls out of the freezer, and put them in the boiling light syrup directly. Reduce the heat to low. To make sure the balls are not stick to the bottom of the pot, use a spoon to scoop them lightly. Wait until they float on the water. Once they are floating, cook for 3 - 4 more minutes. Serve immediately.