Preparation

Step 1: Prepare the Base

1. Line a 20 cm × 20 cm square baking tin with baking paper, ensuring an overhang on the sides for easy removal.
2. In a large mixing bowl, combine the crushed biscuits and cocoa powder.
3. In a saucepan over low heat, melt the butter, Biscoff spread, and brown sugar, stirring until smooth.
4. Remove from heat and stir in the condensed milk, vanilla extract, and salt until well combined.
5. Pour the wet mixture into the dry ingredients and mix thoroughly until the crumbs are evenly coated.
6. Press the mixture firmly into the prepared tin, smoothing the top with a spatula or the back of a spoon.
7. Refrigerate for 30 minutes to set.

Step 2: Prepare the Topping

1. In a heatproof bowl, melt the dark chocolate and coconut oil (if using) over a saucepan of simmering water (double boiler method), stirring until smooth.
2. Pour the melted chocolate over the chilled base, spreading evenly.
3. Melt the Biscoff spread slightly and drizzle over the chocolate layer. Use a skewer or knife to create a swirl pattern.
4. Refrigerate for at least 2 hours, or until fully set.

Step 3: Serve

1. Remove the slice from the tin using the overhanging baking paper.
2. Cut into squares using a sharp knife, wiping the blade clean between cuts for neat slices.
3. Serve chilled and enjoy!