Preheat the oven to 350 degrees Fahrenheit. Prepare a baking dish with parchment paper.
In a saucepan add the butter, and melt until browned and nutty.
Add the browned butter to a large bowl, along with 1⁄2 of the Biscoff spread. Whisk until the Biscoff completely melts into the butter. Then add the brown and white sugar, whisking together until combined.
Crack in the eggs and pour in the vanilla. Whisk the mixture until smooth and shiny.
Sift in the flour and salt, folding together until a thick batter is formed.
Fold in the butterscotch and chocolate chips, along with half of the crushed Biscoff cookies.
Transfer to the parchment covered baking dish and spread the Biscoff batter evenly.
Top with extra chocolate chips, butterscotch chips, and crushed Biscoff cookies.
Bake for 25-20 minutes, or until a toothpick inserted comes out clean.
Let the brownies cool for at least 30 minutes before cutting into squares.
Melt the other half of the Biscoff spread in the microwave, and top with brownies with the melted spread.
Notes
Cocoa Powder: For best results, use high-quality chocolate or cocoa powder.
Parchment Paper: Line your brownie pan with parchment paper to easily remove the brownies.