Decadent seven-layer chocolate mousse cake

Ingredients

• 200g dark chocolate, chopped
• 200g butter, chopped
• 1 1/4 cups (275g) brown sugar
• 3 eggs, lightly whisked
• 3/4 cup (110g) plain flour
• 1/3 cup (35g) cocoa powder
• 1/4 cup (60g) sour cream
• CARAMEL MOUSSE
• 150g white chocolate, chopped
• ½ tsp powdered gelatine
• 1 egg
• ½ cup thickened cream
• 4 tbsp caramel sauce
• 2 egg whites
• 1/2 cup caster sugar
• 1/2 tbsp Cocoa sifted
• 1/2 teaspoon white vinegar
• 150g milk chocolate, chopped
• 150g dark chocolate, chopped
• 1/2 tsp powdered gelatine
• 1/2 cups thickened cream
• 165g caster sugar
• 60ml water
• 65g firmly packed brown sugar
• 150ml thickened cream