Begin by crushing the Biscoff biscuits into fine crumbs using a food processor or a zip-top bag and rolling pin. Mix the crumbs with melted butter until the texture resembles wet sand. Press the mixture firmly into the bottom of a lined rectangular pan, ensuring an even layer. Place the crust in the freezer for about 10–15 minutes to firm up while you prepare the filling.

In a mixing bowl, beat the room-temperature cream cheese with the Biscoff spread until smooth and creamy, which should take about 2 minutes. In a separate bowl, whip the heavy cream with sugar using a hand mixer until soft peaks form, roughly 3–4 minutes.

Carefully fold half of the whipped cream into the Biscoff mixture using a spatula, stirring gently to preserve airiness. Once combined, fold in the remaining whipped cream until just blended, being cautious not to overmix.

Spread half of the cheesecake filling evenly over the chilled crust, smoothing the top with a spatula for a neat finish. Drizzle a layer of Biscoff spread over the filling, then top with the remaining cheesecake filling and smooth the top before refrigerating.

Cover the pan with plastic wrap and chill the Biscoff cheesecake bars in the refrigerator for at least 8 hours, preferably overnight, to allow the dessert to set properly.