01 - Place the chopped dark chocolate in a heatproof bowl set over a pot of simmering water, creating a bain-marie. Stir continuously until the chocolate melts completely and achieves a smooth consistency. Remove from heat and allow to cool slightly while preparing other components.
02 - In a clean, chilled mixing bowl, beat the heavy cream using an electric mixer or whisk until soft peaks form. Place the whipped cream in the refrigerator to maintain its structure until ready to incorporate.
03 - Whisk the egg yolks together with vanilla extract in a separate bowl until well combined. Gradually pour the slightly cooled melted chocolate into the yolk mixture, stirring constantly to temper the eggs and create a smooth, glossy base.
04 - In a spotless bowl, beat the egg whites with a pinch of salt using clean beaters until soft peaks begin to form. Slowly sprinkle in the granulated sugar while continuing to beat. Continue whipping until stiff, glossy peaks form that hold their shape when the beaters are lifted.
05 - Gently fold one-third of the whipped cream into the chocolate base to lighten the mixture. Add the remaining whipped cream and carefully fold until incorporated. Then fold in the beaten egg whites in two additions, using a silicone spatula and rotating motions to preserve the airy structure without deflating the mixture.
06 - Portion the mousse mixture into individual serving glasses or decorative bowls, filling each about three-quarters full. Refrigerate for a minimum of 2 hours, or until the mousse sets completely and holds its shape when touched.
07 - Combine fresh raspberries, powdered sugar, and lemon juice in a blender or food processor. Purée until completely smooth and no fruit chunks remain. For a refined texture, press the mixture through a fine-mesh sieve to remove all seeds. Transfer to a container and refrigerate until serving time.
08 - Remove the chilled mousses from the refrigerator. Spoon a generous layer of the cold raspberry coulis over the top of each mousse portion. Decorate with fresh whole raspberries, chocolate shavings, and fresh mint leaves if desired. Serve immediately while the coulis remains vibrant and the mousse maintains its delicate texture.