Melt the Chocolate and Butter: In a heatproof bowl, combine the chopped chocolate and butter. Place the bowl over a pot of simmering water (double boiler method) and stir until melted and smooth. Remove from heat and let it cool slightly.
Prepare the Egg Yolks: In a medium bowl, whisk the egg yolks until smooth. Gradually whisk the slightly cooled chocolate mixture into the egg yolks until well combined.
Beat the Egg Whites: In a clean, dry bowl, beat the egg whites with an electric mixer on medium speed until soft peaks form. Gradually add the sugar and continue to beat until stiff peaks form.
Whip the Cream: In another bowl, whip the heavy cream until soft peaks form.
Combine Ingredients: Gently fold the egg whites into the chocolate mixture, followed by the whipped cream. Mix until well combined, being careful not to deflate the mixture.
Mold the Mousse: Spoon the mousse into silicone dome molds, smoothing the tops with a spatula. Freeze for at least 4 hours or until firm.
Preparing the Chocolate Coating
Melt the Chocolate and Oil: In a heatproof bowl, combine the chopped chocolate and vegetable oil. Melt over a pot of simmering water or in the microwave in 30-second intervals, stirring until smooth.
Coat the Domes: Remove the frozen mousse domes from the molds. Place them on a wire rack over a baking sheet. Pour the melted chocolate coating over the domes, ensuring they are fully covered. Refrigerate to set the coating.
