1. Stir in a circular motion instead of back and forth motion. A back and forth motion creates lots of air bubbles which will prevent the surface of the egg custard from being smooth. If it does end up with having a lot of bubbles, use a small spoon to scoop out the bubbles, or set aside and wait for a few minutes for the bubbles to go away.
2. Add salt just before cooking the eggs.
3. Cover the container while steaming. Condensed water vapor on the steamer lid will drip down into the bowl. If there is no cover on the bowl, the water will make the surface of the egg custard uneven and look like honeycomb.
4. Add 2 more minute for each additional egg. If you steam too long, the egg will be over cooked and tend to be tough.