Chop the dark chocolate into small pieces and place in a heatproof bowl.
In a saucepan over medium heat, warm 300 g of the heavy cream until it just begins to simmer.
Pour the warmed cream over the chopped chocolate. Let it sit for 5 minutes, then stir until smooth and fully melted. Allow this mixture to cool to room temperature.
In a separate bowl, whip the remaining 300 g of heavy cream to stiff peaks with a hand mixer.
Gently fold the whipped cream into the cooled chocolate mixture until well combined.
Divide the mousse into individual serving dishes and refrigerate for at least 2 hours before serving.
Notes
Chocolate Quality: Using high-quality dark chocolate with around 70% cocoa content will yield a richer flavor.Chilling Time: Allowing the mousse to chill thoroughly ensures the best texture and flavor.Serving Suggestions: Garnish with whipped cream, chocolate shavings, or fresh berries for an elegant touch.Storage: The mousse can be refrigerated for up to 2 days; ensure it's covered to prevent it from absorbing other flavors.