01 -
Line an 8-inch square baking pan with parchment paper, allowing overhang for easy removal. Lightly grease the paper to prevent sticking.
02 -
Combine finely crushed Biscoff biscuits and melted butter in a bowl. Stir until the mixture resembles wet sand and holds when pressed. Press firmly and evenly into the prepared pan using the back of a spoon or flat glass. Refrigerate while preparing the filling.
03 -
In a heatproof bowl, combine sweetened condensed milk, chopped white chocolate, and Biscoff spread. Gently heat in 30-second bursts in the microwave or over a double boiler, stirring until smooth and glossy. Stir in vanilla extract and a pinch of salt.
04 -
Pour the warm filling over the chilled biscuit base and smooth the surface with a spatula. Refrigerate for 2 to 3 hours until firm to the touch.
05 -
Melt 2 tablespoons of Biscoff spread until pourable. Drizzle over the set slice in zig-zag or swirl patterns. Sprinkle with crushed biscuits if desired. Chill for an additional 15 to 20 minutes to set the topping.
06 -
Use the parchment overhang to lift the slice from the pan. Clean a sharp knife between cuts and slice into squares or bars. Serve chilled for best texture and clean edges.