Prepare the pan and oven

• Preheat the oven to 180 °C.
• Line the base and sides of a springform pan with baking paper.

Make the brownie base

• Melt the dark chocolate with the butter in a saucepan over low heat, then let it cool slightly.
• Whisk the eggs with the caster sugar until pale and slightly thickened.
• Fold in the melted chocolate mixture, then the sifted flour, cocoa powder and salt until just combined.

Bake the brownie layer

• Pour the brownie batter into the prepared pan and spread evenly.
• Bake until the top is set but the centre is still slightly fudgy.
• Leave to cool completely in the pan.

Make the Biscoff cheesecake filling

• Beat the cream cheese with the icing sugar until smooth.
• Add the warmed Biscoff spread and mix until fully incorporated.
• Pour in the double cream and whisk until the mixture is thick and creamy.

Assemble and chill

• Spread the cheesecake filling over the cooled brownie base and smooth the top.
• Refrigerate until firm.

Decorate and serve

• Warm a little Biscoff spread and drizzle it over the top.
• Scatter the crushed Biscoff biscuits over the surface.
• Release from the pan, slice and serve.