Line the bottom of a 9-inch springform pan with parchment paper and lightly grease the sides.
Pulse Biscoff cookies in a food processor until finely ground, then stir in melted butter until it resembles damp sand. Press into the pan base and chill for 30 minutes.
Beat cold heavy whipping cream with an electric mixer until stiff peaks form, then refrigerate until needed.
In a separate bowl, beat room-temperature cream cheese until smooth. Add sifted powdered sugar, vanilla extract, and Biscoff spread, beating until fully combined and creamy.
Gently fold the chilled whipped cream into the Biscoff cream cheese mixture in three additions, using a rubber spatula until no white streaks remain.
Spoon the filling over the chilled crust, smooth the top, tap the pan to release air bubbles, and cover with plastic wrap.
Refrigerate for a minimum of 6 hours, or preferably overnight, until completely firm and set.
Gently warm the Biscoff spread until pourable, then pour over the set cheesecake and spread evenly.
Garnish with whole Biscoff cookies and crushed crumbs, refrigerate for 15-20 minutes to set the topping, then release from the pan and serve with clean knife slices.