Biscoff Rice Krispie Treats

Prepare a 9×13 baking pan with nonstick cooking spray and parchment paper. Extend the parchment paper up the sides of the pan to easily remove the rice krispie treats from the pan.
In a large saucepan on the stovetop over medium-low heat, melt the unsalted butter. Add in 20 ounces of mini marshmallows and stir until the marshmallow mixture is melted and smooth. Remove the saucepan from the heat.
Stir in the Biscoff cookie butter spread, vanilla extract, and salt. Then, fold in the Rice Krispies cereal, additional 2 cups of mini marshmallows, and roughly chopped Biscoff cookies until the cereal is well coated in the melted marshmallow mixture.
Pour the Biscoff rice krispie treat mixture into the prepared baking pan. Moisten your hands with water, and gently press the mixture into the pan creating an even layer.
Melt the additional Biscoff spread in the microwave and drizzle it over the rice krispie treat bars with a spoon or piping bag. Press additional broken Biscoff cookies into the top of the rice krispie treats.
Allow the rice krispie treats to set up in the pan for 1 hour before removing and cutting into squares.