Prep everything before starting the cooking portion.
Once everything is prepped, add a non-stick pot on the stove on medium heat and put the butter into the pot. Melt the butter, then add in the marshmallows.
Continue to stir as the marshmallows melt down. Once they are fully melted and combined add in the spice mix along with the salt.
Next, add in the Rice Krispies cereal and the biscoff cookies. Remove the pot from the stove and stir everything together.
Place half in a lined baking pan. Press it down slightly but not too much. You don't want to compact the Rice Krispies too much. Then, spread the Biscoff cookie butter across the bottom layer. Add the remaining Rice Krispies on top and slightly press down until the top is covered. They'll be a little left in the pot, enjoy that.
Allow the rice Krispy treats to set. Do not put them in the fridge, give them time at room temperature. When they are set, they'll be slightly sticky to the touch but they will hold together perfectly for you to cut them and serve.
Use the parchment paper to lift them out of the pan then cut them into squares.