Preheat your oven to 180C/160C Fan, and line a 9x9" square tin with parchment paper.
Melt the Dark Chocolate with the Butter and leave to cools lightly whilst you make the rest of the brownies!
Whisk together the Eggs and Sugar until really thick and mousse like - it will double in volume, be a lot paler, and leave a trail for a couple of seconds before disappearing when done!
Fold the Chocolate/Butter mix into the Eggs/Sugar mix carefully - don't deflate the eggs by being careless!
Add in the Plain Flour and Cocoa Powder, and fold that in as well. Then add in the Biscoff Biscuits, fold through, and pour into the tin.
Using two teaspoons, spoon dollops of Biscoff Spread onto the top of the Brownies.
Bake the Brownies in the oven for 30-35 minutes, or until baked through.
Leave the brownies to cool fully in the tin!