Heat up the oven to 350 degrees and set the rack to the centre. Butter six custard cups a little and put them into a large baking dish. If you are planning to use a metal pan to cook custard, use a newspaper layer to cover the bottom of the pan to keep the temperature even at the bottom.
Take a large bowl and beat eggs in it. Add vanilla extract, sugar and salt to it. Beat and don’t stop until it is dissolved. Add hot milk and into the prepared custards cups, pour egg mixture into it. Use either cinnamon or nutmeg to sprinkle.
Use water to simmer on top of the stove and pour hot water into the baking pan. Put enough water in the pan and make sure that water gets to the level of the custards inside the cup but do not forget to protect your custard from heat.
For about 25 to 30 minutes, keep on baking and wait until it is tender around the edges but still loose in the centre. Your cooking time can vary as it usually depend on the size of the cups you are using for the custard. After 20 minutes, check the custard and keep a close eye on it afterwards.
When you notice that the centre of custard is well set, that’s the time when you can remove it from the oven. Carefully but immediately, remove from oven and give the cups a water bath to remove them. Let it cool down for a while on room temperature. Use a plastic wrap to cover it up and refrigerate for at least 2 hours.