Preheat the oven to 350°F. Lightly spray a 9-inch springform pan with non-stick cooking spray, use a 9-inch parchment circle, and spray again. Set it aside.

Process the Biscoff cookies into a fine crumb. Add the melted butter and a pinch of salt. Continue to pulse the food processor until the mixture is fully incorporated.

Add the crust mixture and press it evenly into the pan without pushing it up the sides. Use a flat surface to press the crumbs evenly.

Bake the crust at 350°F for 10 minutes. Allow to cool. Reduce the temperature to 325°F.

Add cream cheese, cookie butter, both sugars, flour, salt, and vanilla to a large mixing bowl. Using a hand mixer on low speed, mix until smooth and well blended.

Add the eggs individually, scraping the bowl between each addition. Fold in the sour cream. Top the crust with the batter. Smooth the batter before baking.

Place a baking pan under the rack where the cheesecake will bake. Fill the pan halfway with hot water. Bake at 325°F for 30 to 35 minutes, or until the sides are firm but the center is still jiggly. Turn off the oven, leave the door slightly ajar, and let the cheesecake cool slowly in the warm environment for 60 minutes. Remove the cheesecake and let it cool at room temperature before chilling. Chill the cheesecake for at least 2 hours (but up to 48 hours) in the refrigerator before removing it from the springform pan and topping it with melted cookie butter.

In a microwave-safe bowl, heat the cookie butter for 15 seconds. Stir and microwave in 5-second intervals as needed until the mixture is smooth.

Pour the cookie butter evenly over the cheesecake, spreading it to the edge as desired, using a spiral method to smooth the final look—working from the outside in toward the center. Sprinkle crushed cookies along the outside border. Chill in the refrigerator until the cookie butter is set, for at least 30 minutes, before cutting and serving the cheesecake.