- Crack eggs into a large mixing bowl and add sugar. Whisk until light and fluffy. Pour in oil and milk and continue whisking until smooth. Slowly add in flour and custard powder while whisking until smooth batter is formed. Also, gradually add in baking powder, baking soda and salt and whisk until smooth, ensuring there are no lumps. Cover the mixing bowl with cling wrap and allow the batter to rest for at least 30 mins.
- Prepare a steamer and bring water to a rolling boil. Place a 9-inch round pan into the steamer for about 3 mins to warm it up. Then, pour the batter into the pan and steam for 40 mins. To check if it’s ready, insert a tooth pick into the centre of the cake and remove it. The tooth pick should come out clean.
- Take the cake out from the steamer and set aside to cool down slightly. Serve warm or at room temperature.