Neapolitan Marble Bundt Cake

Ingredients

• 1 1/2 cups (340g) unsalted butter, room temperature
• 2 1/4 cups (450g) caster sugar or granulated sugar
• 6 large eggs
• 2 tsp vanilla extract
• 2/3 cup (85g) plain flour
• 1/3 cup + 1 Tbsp (50g) cocoa powder
• 1 tsp baking powder
• 1/2 tsp fine sea salt
• 3 Tbsp (40ml) sour cream
• 2 cups (250g) plain flour
• 2 tsp baking powder
• 1 tsp fine sea salt
• 1/3 cup (80ml) sour cream
• 2 2/3 ounces (75g) white chocolate, finely chopped
• 3 Tbsp freeze dried raspberry powder
• A little red gel food colouring
• 1 1/4 cups (150g) icing sugar
• 2 + 1/2 Tbsp milk
• 1 tsp vanilla bean paste
• Small pinch of salt.