Whisk together egg yolks, 2 Tbsp sugar and ¾ cup heavy cream in medium saucepan over medium-low heat, approximately 3-4 minutes (be careful not to overcook; remove from heat when mixture sticks to back of spoon).
Add melted chocolate and vanilla. Strain and allow mixture to cool.
With electric mixer whisk remaining heavy cream and sugar until stiff peaks form. Set aside and refrigerate 1 cup of whipped cream for mousse topping.
When chocolate mixture is completely cool, gently fold in non-topping whipped cream.
Carefully fill serving containers and refrigerate, a minimum of 3 hours.
Before serving, add small dollop of whipped cream and a grated chocolate!
Notes
Use a microplane to grate chocolate for an extra special garnish!