Step 1

Heat the chocolate, 1 cup of the cream, and the marshmallows in a dry, heatproof bowl over a pot of simmering water, stirring until completely melted (about 10 minutes).

Step 2

Remove from heat and allow to cool to room temperature (about 1 hour).

Step 3

Beat remaining cream to soft peaks. Gently fold 1/3 of the softly whipped cream at a time into chocolate mixture.

Step 4

Spoon the mousse into 6 dessert glasses or bowls. Cover and refrigerate for at least 4 hours or overnight.

Step 5

Serve with a dollop of whipped cream and chocolate shavings if desired.