• 125g (4½ oz / ½ cup) butter, softened
• 115g (4oz / ½ cup) caster (superfine) sugar
• 1 teaspoon natural vanilla extract
• 2 eggs
• 125g (4½ oz / 1 cup) plain (all-purpose flour)
• 60g (2¼ oz / ½ cup) unsweetened cocoa powder
• 2 teaspoons baking powder
• 100ml (3½ fl oz) milk
• 60g (2¼ oz / heaped â…“ cup) finely chopped dark chocolate

Coffee liquer mocha sauce - 30g (1 oz) butter - 80g (2¾ oz / ½ cup) chopped dark chocolate - 170ml (5½ fl oz / â…” cup) pouring (whipping) cream - 1 teaspoon instant coffee granules - 2 tablespoons coffee-flavoured liquer (such as creme de cacao or kahlua) - 23g (1¼ oz / ¼ cup) roasted hazelnuts, skined and chopped [Note 1 & 2]- pouring (whipping) cream, to serve (optional) - fresh berries, to serve, optional