Break the chocolate into squares and place in a bowl. Add half the whipping cream to the bowl and melt in a microwave oven or double boiler until the mixture is even.

Cool the chocolate mixture in the refrigerator for at least two to three hours, or until it is completely cold.

Transfer the cold chocolate mixture to a mixer bowl and add the remaining cream. Whip together at high speed until you get an even, slightly soft mousse.

Transfer the mousse to a piping bag and fill the cups up to two-thirds full.

Garnish with grated chocolate and serve.