Make the Crust : Preheat your oven to 325°F (163°C). Grease a 9-inch springform pan and wrap the outside with aluminum foil to prevent leaks. In a bowl, combine the Biscoff cookie crumbs, melted butter, and granulated sugar (if using). Mix until the crumbs are evenly coated. Press the mixture firmly into the bottom of the prepared pan to form an even crust. Bake for 10 minutes, then set aside to cool.

Prepare the Cheesecake Filling : In a large bowl, beat the softened cream cheese and sugar together until smooth and creamy. Add the vanilla extract, followed by the eggs, one at a time, mixing well after each addition. Mix in the sour cream and heavy cream until the batter is smooth. Warm the Biscoff cookie spread slightly (to make it easier to incorporate) and gently fold it into the batter, creating swirls for a marbled effect.

Bake the Cheesecake : Pour the cheesecake batter over the cooled crust. Place the springform pan in a larger baking dish and pour hot water into the dish until it reaches halfway up the sides of the springform pan. Bake in the preheated oven for 55-65 minutes, or until the edges are set but the center is slightly jiggly. Turn off the oven, crack the door open slightly, and let the cheesecake cool in the oven for 1 hour. Then, transfer to the refrigerator to chill for at least 6 hours or overnight.

Make the Salted Caramel Sauce : In a small saucepan, melt the butter over medium heat. Stir in the brown sugar and cook for 2-3 minutes until combined and bubbling. Slowly whisk in the heavy cream and sea salt. Reduce heat to low and simmer for another 2-3 minutes, stirring constantly. Remove from heat and let cool to room temperature.

Assemble and Serve : Once the cheesecake is fully chilled, pour the salted caramel sauce over the top, spreading it evenly. Sprinkle a pinch of sea salt over the caramel, if desired. Slice, serve, and enjoy the creamy, caramel-rich perfection of your Biscoff Salted Caramel Cheesecake!