01Melt chocolate in double boiler, stirring until smooth. Alternatively, place chocolate in microwave safe bowl and heat 15 seconds at a time, stirring in between, until melted and smooth. Let cool to room temperature.
02Combine cream, sugar and vanilla in large mixing bowl. Beat with electric mixer until stiff peaks form.
03Combine cooled chocolate and mascarpone in medium mixing bowl and whisk until combined. Gently fold in half of whipped cream until combined. Refrigerate remaining whipped cream until ready to serve.
04Spoon or pipe mousse into individual serving glasses. Refrigerate until ready to serve. When ready to serve, top mousse with whipped cream and garnish with chocolate shavings.