01 - Gently melt dark chocolate in a heatproof bowl over simmering water or using short bursts in a microwave until smooth.
02 - Coat silicone dome molds (3" diameter) with an even layer of melted chocolate using a pastry brush or spoon. Chill molds for 10 minutes to set the chocolate, then repeat with a second coat. Refrigerate for 30 minutes or until fully set.
03 - Soften gelatin sheets in cold water for 5 minutes, or sprinkle powdered gelatin over 2 tablespoons cold water and allow to bloom.
04 - Whisk mascarpone, powdered sugar, and vanilla in a mixing bowl until smooth and combined.
05 - Whip heavy cream to soft peaks and gently fold it into the mascarpone mixture until fully incorporated.
06 - Warm bloomed gelatin gently until dissolved, then fold into the mascarpone mousse to ensure even distribution.
07 - Spoon or pipe the mousse into each chocolate shell, filling nearly to the top and smoothing the surface. Refrigerate domes for a minimum of 3 hours to set.
08 - Carefully unmold domes and arrange on a wire rack set over a tray for glazing.
09 - Soften gelatin in 3 tablespoons cold water. Set aside.
10 - Combine water, sugar, cream, and sifted cocoa powder in a saucepan. Bring to a simmer over medium heat, whisking continuously until fully smooth. Remove from heat and allow to cool briefly (to 122°F).
11 - Add the softened gelatin to the warm chocolate glaze, whisking until fully dissolved. Cool glaze further to approximately 90°F for ideal consistency.
12 - Pour cooled mirror glaze evenly over each dome, allowing excess to drip off the sides. Chill domes for at least 30 minutes to set the glaze.
13 - Transfer domes onto serving plates. Garnish with edible gold leaf, chocolate curls, or fresh berries as desired.