Method

• 1.
  Preheat oven to 180°C/160°C fan-forced. Grease base and sides of a 20cm square cake pan and line with baking paper.
• 2.
  Place butter, chocolate and cocoa powder in a medium heatproof bowl and place over a pan of simmering water (don’t let base of bowl touch the water). Cook, stirring constantly, until melted and smooth. Remove bowl from pan.
• 3.
  Place the sugar and eggs in a large heatproof bowl and stir until smooth. Stir in the warm chocolate mixture, then stir in the flour and 1/4 tsp fine salt until you have a smooth batter. Pour batter into prepared pan. Bake for 20 minutes or until edges are firm but the middle is still a little soft. Set on a wire rack to cool completely in pan. I like to chill the brownie until I’m ready to serve, so I can cut the brownies into neat little squares.
• 4.
  For the custard, place egg yolks, sugar, cornflour and cocoa powder in a large heatproof bowl and whisk until smooth.
• 5.
  Place the milk and a pinch of fine salt in a medium saucepan over medium heat. Cook until steaming but not boiling. Stir in the instant coffee to dissolve. Pour half of the hot milk mixture into the egg mixture while whisking constantly to quickly combine. Slowly pour in the rest of the milk while whisking continuously.
• 6.
  Pour everything back into same pan over medium heat. Cook, stirring constantly, until custard starts to thicken. Once it comes to the boil and starts to bubble, remove from heat. Immediately stir in the chopped chocolate until melted, combined and smooth. Pour it into a clean, shallow bowl and cover with plastic wrap, so the wrap touches the surface of the custard. Let custard cool to room temperature before chilling in the fridge until ready to assemble.
• 7.
  For the corn flake crunch, line a small baking tray with baking paper and set aside.
• 8.
  Place the sugar and 3 tsp water in a small saucepan over medium-high heat. Cook, swirling pan occasionally, until sugar dissolves and the mixture comes to the boil. Add the hazelnuts and corn flakes and stir to coat. The mixture will look like it has crystallised, but keep stirring until the sugar melts into a deep amber colour and coats the corn flakes evenly.
• 9.
  Spoon mixture onto prepared tray in as thin a layer as possible. Be careful here, as the mixture will be extremely hot. Set aside to cool completely. Once cool, break up into smaller chunks.
• 10.
  When you’re ready to assemble, cut brownie into small chunks and give the custard a good whisk to remove any lumps. Layer up the elements in small serving glasses or ramekins and top with a scoop of ice cream and the corn flake crunch.