Begin by greasing and lining an 8x8 inch square baking tin with parchment paper.

Preheat your oven to 200°C (or 180°C for a fan oven, Gas Mark 6).

In a heatproof bowl, finely chop the dark chocolate and add the butter. Melt over a pot of simmering water.

Sift together the all-purpose flour and sea salt. Gradually fold this dry mixture into your melted chocolate mixture.

Crack the eggs into the chocolate batter, gently stirring until smooth.

Pour the brownie batter into the prepared tin and bake for 35 minutes.

Let the brownies cool completely in the tin on a wire rack.

In a medium saucepan, gently heat the sugar until it melts into a golden-brown caramel. Stir in the cream, butter, salt, and vanilla extract.

Remove the caramel from heat and allow it to cool slightly. Coat the cornflakes in the caramel.

Spread the caramel-coated cornflakes over the cooled brownies.

Let the assembled brownies sit at room temperature to allow the caramel to set.