1) Fill the steamer with water and let it heat.
2) In a large bowl, whisk the eggs and mix in the sugar.
3) Mix the flour and vanilla pudding powder together.
4) Sift the flour mixture into the egg mixture. Mix well with the help of a spatula. Ensure that no lumps have been formed.
5) Add the milk, mix well and cover the bowl with a plastic sheet. Let the mixture stand in a cool, dry place till bubbles have formed on the surface.
8) Mix the baking powder with some water and add the mixture to the cake mixture.
9) Next, add the melted butter and mix well.
10) Line the Chinese bamboo steamer basket with a baking paper and pour the batter into it.
11) Place the basket in the steamer, over the now boiling water, and let the cake steam and cook for 20-25 minutes.
12) Carefully remove the cake and separate it from the baking paper. Transfer to a serving plate and then serve while still hot, or cool before serving. Cut into wedges.