Heat 0.5 cups of heavy cream in a microwave-safe bowl for 50 seconds until warm.

Add the chocolate chips to the warm cream and stir until melted. Let it cool slightly.

In a medium bowl, beat the remaining 1 cup of heavy cream until soft peaks form and then stiff peaks.

Gently fold the cooled chocolate mixture into the whipped cream until well combined.

Divide the mousse into serving glasses and refrigerate for at least 1 hour before serving.

Top with additional whipped cream or chocolate shavings before serving.