Cranberry trifle with choc-dipped cherries

Ingredients

• Custard
• 2 1/3 cup (580ml) pouring cream
• 1 1/4 cup (310ml) milk
• 5 egg yolks
• 3/4 cup (165g) caster sugar
• 2 teaspoon cornflour
• 1 teaspoon vanilla bean paste
• 3 cup (750ml) cranberry juice
• 1/3 cup (80ml) boiling water
• 2 1/2 tablespoon gelatin powder
• 16 savoiardi (sponge fingers), cut in half
• 12 cherries, stems attached
• 50 gram white eating chocolate, melted
• 300 millilitre thickened cream
• 1/2 cup (80g) icing sugar, plus extra for dusting (optional)