Heat chocolate in a double boiler until melted.

In a medium saucepan, heat 1/2 cup heavy cream on medium heat until tiny bubbles form all around the edges.

In a bowl whisk egg yolks, then stir this into the heated cream and cook until it reaches 160 degrees F.

Strain mixture if the eggs clump a bit, straining it will make the mixture smooth.

Whisk egg mixture into the chocolate and allow it to cool. Place a bowl of cold water and ice under the bowl of egg mixture and chocolate to speed this along,

While the mixture is cooling, whip 1 1/2 cups heavy cream until stiff peaks form.

Gently blend cooled egg mixture into whipped heavy cream with a spatula and add vanilla extract.

Pour into dishes and refrigerate until cold. About 3 hours.