In a small bowl, whisk the egg yolks and 1 tablespoon of sugar. Set aside.
In a small saucepan, combine the cream, chocolate, and 1 tablespoon sugar. Heat over medium-low heat until the chocolate is melted and the mixture is smooth, stirring constantly, about 5 minutes.
Remove the pan from the heat. Stir in the vanilla. Mix a small amount of the hot chocolate filling into the egg yolk mixture. Slowly pour the entire egg yolk mixture into the pan, stirring constantly.
Divide the mixture among four (6-ounce) ramekins. Place the ramekins in a baking pan. Add 1 inch of boiling water to the pan.
Bake uncovered for 40 to 45 minutes, or until the center is almost set. Remove the ramekins from the water bath and place on a rack to cool for 10 minutes.
Sprinkle the remaining 1 tablespoon of sugar evenly over the custards. Heat the sweetener with a torch or under the broiler for 2 to 4 minutes, or until the sweetener is browned. Refrigerate for 2 to 4 hours until firm.
Notes
Pay attention to your cooking temperature and time. Overcooking your custard at too high of heat can cause it to turn grainy and dry.
Once you've caramelized the sugar topping, let it sit for a few minutes until it cools slightly. Then put the custard into the refrigerator for at least 2 hours before serving so that it has time to set properly.