8 ouncesbittersweet or semi sweet chocolatechopped
In a medium sized saucepan, whisk egg yolks, sugar, vanilla, and 1 cup of heavy cream. Heat over medium-low to medium heat for about 5 minutes until mixture is hot and coats the back of a spoon. Do not boil!
Pour the hot cream mixture over the chopped chocolate. Continue stirring the mixture until the chocolate is completely melted and the mixture is smooth. Chill until cool.
With a hand mixer or stand mixer, beat on medium high speed the remaining 1 1/2 cups heavy cream until stiff beaks form.
Fold 1/3 of the whipped cream into the chocolate mixture with a rubber spatula. Once the whipped cream is well incorporated, fold the remaining 2/3 of the whipped cream into the mixture.
Scoop the chocolate mousse into serving dishes, cover, and chill for at least 30 minutes.