In a mixing bowl, beat the room-temperature butter and sugar together until light and fluffy. This should take about 3-5 minutes.
Stir in the melted and cooled unsweetened chocolate along with the vanilla extract. Mix until well combined.
Add the pasteurized egg to the chocolate mixture, mixing thoroughly until it is fully incorporated.
In a separate bowl, whip the heavy cream until it starts to thicken. Gradually add the powdered sugar and the additional vanilla, continuing to whip until soft peaks form.
Gently fold the whipped cream into the chocolate mixture.
Carefully spoon or pipe the French silk mixture into your shooter glasses.
Place the shooters in the refrigerator for at least 2 hours, allowing the flavors to meld and the dessert to set.