In a small saucepan over medium heat, combine pomegranate juice and sugar, stirring until dissolved, about 3-5 minutes. Bloom the gelatin by sprinkling it over 2 tablespoons of cold water for 5 minutes. Once warm, add gelatin and stir until dissolved. Cool slightly before folding in whipped cream.

Preheat oven to 350°F (175°C) and line a baking pan with parchment paper. Beat eggs and sugar until light and pale, about 5-7 minutes. Gradually add melted butter and vanilla, mixing until incorporated. Sift in flour and fold gently until no streaks remain. Pour batter into prepared pan.

Bake sponge in preheated oven for 20-25 minutes, or until a toothpick inserted in the center comes out clean. Cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.

Use a round cookie cutter to cut out disks from the sponge base and place each disk in dome molds. Layer with pomegranate mousse, filling molds completely and smoothing the top.

Cover molds with plastic wrap and freeze for at least 4 hours until mousse is firm, allowing for day-ahead preparation.

In a saucepan over medium heat, combine pomegranate juice and sugar until dissolved, about 3-5 minutes. Bloom the gelatin in cold water and whisk into warm juice. Remove from heat and stir in chopped white chocolate until smooth. Cool slightly to around 90-95°F before applying.

Carefully unmold frozen mousse domes onto a wire rack. Pour cooled mirror glaze over each, ensuring even coverage. Let set for about 10 minutes before transferring to a platter. Serve chilled.