1. Mix all the ingredients except onion, blend them well together.
2. Preheat the baking tray for 3 minutes in the 350 degree Fahrenheit oven, then take it out and pour the mixture in and put the tray back in the oven, broil it for 30 minutes. The custard should have gold brown surface.
3. Fry the onion in hot cooking oil until it becomes gold and brown, separate it from the oil. Spread it on the surface of the custard at the 20th minute and continue baking. The onion will add to the flavor of the custard.
4. Serve when the custard is cooled down.