Pour the heavy cream into a metal or ceramic bowl. With a large wire balloon whisk, whisk the cream until it thickens, just until it will still fall off a spoon. How long you have to whisk will depend on how thick your cream is, but generally it will take 4-5 minutes to get to the right consistency. Gently whisk in two tablespoons of the hazelnut chocolate sauce until there are no streaks. You can add more if you’d like a more intense chocolate flavor to the mousse. Spoon into champagne coupes, and top with the crushed pistachios, if desired.

Pour the heavy cream into a metal or ceramic bowl. With a large wire balloon whisk, whisk the cream until it thickens, just until it will still fall off a spoon. How long you have to whisk will depend on how thick your cream is, but generally it will take 4-5 minutes to get to the right consistency. Gently whisk in two tablespoons of the hazelnut chocolate sauce until there are no streaks. You can add more if you’d like a more intense chocolate flavor to the mousse. Spoon into champagne coupes, and top with the crushed pistachios, if desired. Refrigerate at least an hour and up to 5 hours before serving. Also makes a great leftover breakfast the next morning.