Peel, grate and squeeze ginger to get ginger juice. Set aside.
Melt rock sugar with boiled water. After sugar has melted, add remaining cold water.
In another bowl, lightly beat eggs.
Add ginger juice through a fine strainer to eggs.
Add sugar mixture to eggs and lightly mix.
Pour mixture through a fine strainer into bowls / ramekins.
Open Instant Pot. Add 1 cup of water and trivet into Instant Pot liner.
Place 3 bowls on trivet. You can stack another 3 on top using another trivet in between if you like.
Close the Instant Pot. Select Steam for 10 minutes.
When done, quick release and serve.