6tablespoons butter, softened
• 200g caster sugar
• 1 egg
• 250g plain flour
• 5 tablespoons unsweetened cocoa
• 1 1/2 teaspoons bicarbonate of soda
• 1 teaspoon salt
• 225ml milk
• 1 teaspoon vanilla extract
• Filling
• 175g butter, softened
• 90g icing sugar
• 1/4 teaspoon vanilla extract
• 100g marshmallow creme
• 1 tablespoon milk