Preheat your oven to 350°F (175°C). In a mixing bowl, combine Biscoff cookie crumbs, Biscoff cookie butter, melted unsalted butter, brown sugar, and a pinch of salt. Stir until the mixture is well combined and resembles wet sand. Press this mixture tightly into a greased 9-inch springform pan. Bake for 10 minutes, then let it cool completely.

While the crust is cooling, take cream cheese, eggs, sour cream, and Biscoff cookie butter out to reach room temperature. In a large mixing bowl, beat the cream cheese until smooth and creamy. Gradually add granulated sugar and Biscoff cookie butter, mixing until combined.

With the mixer on low speed, add the eggs one at a time, ensuring each is fully incorporated before the next. Mix in the sour cream, heavy cream, and vanilla extract until silky smooth.

Wrap the springform pan in aluminum foil to create a water bath barrier. Place the pan in a larger roasting pan and fill with hot water halfway. Pour the filling over the cooled crust and bake at 325°F (160°C) for 60–70 minutes, until set around the edges but slightly jiggly in the center.

Turn off the oven and crack the door open, allowing the cheesecake to rest for 1 hour. Cool to room temperature on a wire rack before refrigerating for at least 8 hours, preferably overnight.

On the day of serving, whip chilled heavy cream with powdered sugar until stiff peaks form. Once cheesecake has chilled fully, remove from the springform pan, transfer to a serving plate, and pipe rosettes of whipped cream on top, garnished with Biscoff cookies and cookie crumbs.