The secret to dun dan (steamed egg dessert)

I just made the most perfect Dun Dan. Here's the recipe:

1 tbsp ginger juice
2 tbsp sugar
2 tbsp hot water
1 egg
Enough milk to make 1 cup

Boil water in a steamer pot on high heat.

Grate ginger and squeeze out the juice. Add sugar and hot water and stir until sugar dissolves. Add egg and beat. Add milk until you get 1 cup of liquid. Strain into a bowl. Put the bowl into the steamer and close the lid.

Now here's the secret: TURN OFF THE HEAT

Let the Dun Dan steam in the steamer with no heat for 15 minutes. Open the lid and enjoy your perfect Dun Dan!