Biscoff Brownies

Grease and line a 33 x 23cm brownie tin with baking paper, ensuring two sides of the paper overhang. Preheat oven to 180ºC (160ºC Fan). In a pan melt the butter over a medium heat.  As the butter melts it will begin to foam. The colour will change from yellow to golden to finally toasty brown.  Once you smell the nutty aroma remove from the heat and pour into a jug to stop the butter cooking any further. In a food processor, blitz the biscuits until they resemble fine crumbs. Pour in the melted brown butter and give it a stir until the crumb is moist and they stick together. Place the biscuit mixture into your prepared tin and press down using the back of a spoon until you have a nice even layer. Put into fridge to set. Put a large heat-proof bowl over a saucepan of simmering water to create a bain marie. Add 250g of chocolate chips and butter to bowl. Stir occasionally until melted together. Remove bowl from heat, then whisk in sugar.  Add eggs one at a time, whisking for 1 minute after each egg. Fold in flour mixture until combined, then fold in remaining 100g of chocolate chips. Pour batter on top of the biscuit base and smooth the top.  Melt the Biscoff spread in a microwave safe bowl for 15-30 seconds. Pour the spread over the brownie batter in 3 long strips lengthwise. Use a knife to swirl the spread, dragging it in the opposite direction. Bake until a toothpick inserted in middle comes out with a few moist crumbs, approx 35-40 minutes. Let cool in the baking tray for 30 minutes before using parchment paper to remove from pan.