Preheat the oven to 350°F.

Pulse the Biscoff cookies in a food processor until finely ground.

Add the melted butter and sugar to the cookie crumbs and pulse until combined.

Prepare a 9-inch springform pan by wrapping the bottom and sides with several layers of aluminum foil to prevent water from seeping in during baking.

Press the cookie crumb mixture into the bottom and about an inch up the sides of the pan.

Bake the crust for 10 minutes, then let it cool completely.

Preheat the oven to 350°F if it’s not still preheated from the crust.

In a stand mixer, beat the softened cream cheese, cornstarch, and granulated sugar together with a paddle attachment for two minutes until smooth and lump-free.

Add the Biscoff cookie butter, vanilla extract, and sour cream to the cream cheese mixture. Mix for 1 minute until well combined.

Boil a pot of water for the water bath.

Add the eggs and egg yolks one at a time, mixing each one fully before adding the next. Do not overmix.

Pour the batter into the prepared crust. Place the cheesecake in a large roasting pan and pour the boiling water into the pan until it reaches about 1 ½ inches up the sides of the springform pan.

Bake at 350°F for 1 hour. After an hour, turn off the oven and crack the oven door open, letting the cheesecake sit for another hour to cool gradually.

After 2 hours, remove the cheesecake from the oven, run a butter knife around the edges to loosen it from the pan, and let it cool completely on the counter. Refrigerate for at least 8 hours, or overnight.

Once chilled, remove the cheesecake from the springform pan and transfer it to a serving plate.

Pour the melted Biscoff cookie butter over the top and use a mini offset spatula to smooth it out. Refrigerate for about 20 minutes until the topping is set.

Decorate with whipped cream swirls, Biscoff cookie crumbs, and whole Biscoff cookies if desired.