• Preheat the oven to 180 degrees Celsius/ 360 degrees Fahrenheit. If you are using a glass or ceramic dish instead of a metallic pot for making the crème caramel, place it in the oven as well, so that it can get hot before you pour the caramel into it.

Crème:

• Mix together the eggs, sugar, and milk. Scrape the seeds of the vanilla bean and add them to the mixture or add the vanilla extract if that is what you are using.
• Let the mixture rest while you make the caramel.

Caramel:

• You can use a metallic pot, inside of which you can bake the custard as well. If you don't have that, you can make the caramel in a regular pan and pour the caramel carefully into a casserole dish, a glass or ceramic one would be perfect.
• Either way, add the sugar to the pot or pan. Let it untouched until it starts to melt, then start stirring carefully.
• Let it caramelize until it reaches a nice amber color, but pay attention and don't let it get too dark.
• For the next step, it is better to wear protective kitchen gloves, hot sugar can cause major burns. If using the metallic pot, grab it by the handles and start rotating it carefully to distribute the caramel evenly on the bottom and walls of the pan.
• If using a preheated casserole dish, quickly but very carefully pour the sugar into the dish and quickly rotate the dish to distribute the caramelized sugar on the bottom and the walls of the dish. It is better to heat the casserole dish in the oven before spreading the caramel sugar in it, it will give you a few extra moments time to evenly distribute the sugar before it hardens.
• Leave the pot or the dish stand for a couple of minutes until the caramel becomes hard, then pour the egg and milk mixture into the pot.

Bake:

• Place the dish into another baking dish with somewhat higher walls. Pour some tepid water into the baking dish, so much that the dish containing the crème caramel stands halfway in the water.
• Bake the crème caramel for about 30 minutes.
• Check if it is done by carefully lifting the dish from the water and shaking it gently. If it still makes waves underneath the surface then it is still not ready. If so, place it back into the water and continue baking it, checking again after 10 minutes or so.
• When done, it should jiggle only slightly in the middle, then you can take it out and be sure that by the time it is cold, it will be set and cooked through, but still silky smooth.
• Let cool completely at room temperature. The crème caramel will lose much of its volume when getting cold, don't worry about it, it is supposed to be so.
• When cool, place it in the fridge and let stand for several hours or better overnight.

Serve:

• Before turning the crème caramel onto the serving plate or platter, run a knife around the edges of the custard, so that it will not stick to the walls of the dish.
• Place a large plate or platter on top of the dish, grab the plate and the dish properly and turn the dish upside down. The crème caramel will gently fall onto the serving platter and the caramel will distribute itself on top and around the flan.
• Slice and serve.