Step 1

For the brownies, preheat the oven to 180°C (160°C fan/350°F/gas mark 4). Grease a 20-cm (8-in) square cake pan and line with baking paper.

Step 2

Add the butter, chocolate and cocoa powder to a heatproof bowl and place it over a pan of simmering water, stirring gently until it’s completely melted. Set aside.

Step 3

Add the sugar and eggs to a bowl and mix until smooth. Stir in the chocolate mixture and then mix in the flour and salt until you have a smooth batter.

Step 4

Pour the batter into the tin and bake for 18–23 minutes or until the edges are firm but the middle is still a little soft. Remove from the oven and set aside to cool completely. I like to chill these in the fridge until I’m ready to use, so I can cut the brownies into neat little squares.

Step 5

To make the custard, add the egg yolks, sugar, cornflour and cocoa powder to a heatproof bowl and whisk until smooth. Add the milk and salt to a small saucepan and heat until steaming but not boiling. Stir in the instant coffee to dissolve. Pour half of the hot milk onto the eggs while whisking to quickly combine. Slowly pour in the rest of the milk while whisking continuously.

Step 6

Pour everything back into the pan and heat it gently while stirring, until the custard starts to thicken. Once it comes to the boil and starts to bubble, remove from the heat and stir in the chopped chocolate until it melts. Pour it into a clean, shallow bowl and cover with plastic wrap, so it touches the surface of the custard. Let it cool to room temperature before chilling in the fridge.

Step 7

To make the cornflake crunch, line a small baking tray with baking paper and set aside. Add the sugar and water to a pan and heat gently until the sugar is melted and the mixture comes to the boil. Tip in the chopped nuts and cornflakes and stir to coat. The mixture will look like it has crystallized but keep stirring until the sugar melts into a deep amber colour and coats the cornflakes.

Step 8

Remove from the heat and pour it onto the lined tray to cool completely. Be careful here as the mixture will be extremely hot. Once cool, break up the cornflakes into smaller chunks.

Step 9

When you’re ready to assemble, slice the brownie into small chunks and give the custard a good whisk to remove any lumps. Layer up the elements in small ramekins and top with a scoop of ice cream and more cornflake crunch.