01 - Melt 7 ounces chopped dark chocolate in a microwave-safe bowl or over a double boiler until smooth. Using a pastry brush or spoon, coat the insides of 6 silicone or paper cupcake liners with melted chocolate, creating an even layer. Place the liners on a tray and chill in the refrigerator for 20 minutes, or until set. Once firm, carefully peel off the liners, leaving you with chocolate cups.
02 - In a microwave or double boiler, gently melt 3.5 ounces dark chocolate and let it cool slightly. In a chilled bowl, whip the heavy cream with powdered sugar and vanilla extract until soft peaks form. Fold a spoonful of whipped cream into the melted chocolate to lighten, then gently fold the chocolate mixture into the remaining whipped cream until fully combined and smooth.
03 - Pipe or spoon chocolate mousse into each chocolate cup, filling about two-thirds full. Garnish with fresh berries, chopped nuts, mini marshmallows, chocolate curls, and edible gold decorations as desired.
04 - Chill the assembled cups in the refrigerator for at least 20 minutes before serving to allow flavors to meld and mousse to set properly.