Preheat the oven with a water bath to 180°C (350°F).
First, place your empty ramekins in the baking dish of your choice.
Fill the dish with boiling water, up to 1 cm below the ramekins.
Remove the ramekins and place the dish in the oven; it will be easier to handle without them.
You can then fill the ramekins with the flan mixture and place them in the oven, directly in the dish.
The water will then be at the ideal level!