1-Grease and line a 20cm/8″ square tin: Grease and line a 20cm/8″ square tin with baking paper.
2-Crush the Digestive (or alternative) biscuits in: Crush the Digestive (or alternative) biscuits in a ziplock bag with a rolling pin until they are fine crumbs.
3-Add the Biscoff Biscuits and crush, leaving: Add the Biscoff Biscuits and crush, leaving some bigger chunks.
4-Melt the butter, sugar, golden syrup, cocoa,: Melt the butter, sugar, golden syrup, cocoa, and Biscoff Spread together in a large saucepan on the stovetop.
5-Once the mixture has melted, remove the: Once the mixture has melted, remove the pan from the heat and add the biscuit mixture. Stir everything together well so the biscuits are completely coated in the butter mixture.
6-Transfer the mixture to your prepared tin: Transfer the mixture to your prepared tin and press it down into a compact even layer with the back of a spoon.
7-Melt the chocolate in the microwave in: Melt the chocolate in the microwave in 30-second bursts, stirring in between. Pour the melted chocolate over the top of the tiffin base, smoothing it out into an even layer.
8-Melt the Biscoff Spread for the topping: Melt the Biscoff Spread for the topping in the microwave for 30 seconds, or until it’s runny. Pour over the chocolate in a swirling sort of pattern. Take a skewer and swirl through melted chocolate and Biscoff spread to create a messy swirling design.
9-Put the tin in the fridge for: Put the tin in the fridge for at least 2 hours to set the topping.
10-To prevent the chocolate layer on top: To prevent the chocolate layer on top from cracking when you cut into it, allow the Tiffin to come to room temperature again before slicing. Slice up into 16 squares and enjoy!