The watery mixture should start to thicken. This can take anywhere from 2-8 minutes. Once your mixture thickens, remove from the heat. Stir in your vanilla extract.
Immediately pour your custard mixture into the ramekins and cover with plastic wrap, make sure the wrap is touching the top of the custard to prevent a skin from forming. Place the ramekins in the refrigerator to chill for at least 4 hours or overnight.
When ready, sprinkle each ramekin with one tbsp of sugar and use a kitchen torch to melt the sugar OR place your ramekins in the oven with the broiler on, making sure to watch closely as to not burn the sugar. Allow sugar to harden and enjoy!