Step 1: Prepare the Crust

1. Preheat your oven to 325°F (160°C). Grease a 9-inch springform pan and line the bottom with parchment paper for easy removal.
2. In a mixing bowl, combine the Biscoff cookie crumbs and melted butter. Mix until the crumbs are evenly coated and resemble wet sand.
3. Press the mixture firmly into the bottom of the prepared pan, using the back of a spoon or the bottom of a glass to create an even layer.
4. Bake the crust for 10 minutes. Remove from the oven and let it cool while you prepare the filling.

Step 2: Make the Cheesecake Filling

1. In a large mixing bowl, beat the softened cream cheese with a hand or stand mixer on medium speed until smooth and creamy, about 2–3 minutes.
2. Add the granulated sugar and brown sugar, mixing until fully incorporated.
3. Beat in the eggs one at a time, scraping down the sides of the bowl as needed.
4. Add the sour cream, heavy cream, and vanilla extract, mixing just until combined. Avoid overmixing, as it can incorporate too much air and cause cracks during baking.

Step 3: Assemble and Bake

1. Pour the cheesecake filling over the cooled crust, spreading it into an even layer.
2. Place the springform pan on a large sheet of aluminum foil and wrap the foil tightly around the bottom and sides to prevent water from seeping in.
3. Place the pan in a large roasting dish and pour hot water into the dish until it reaches halfway up the sides of the springform pan, creating a water bath.
4. Bake for 55–65 minutes, or until the edges are set but the center is slightly jiggly. Turn off the oven and crack the door open slightly, allowing the cheesecake to cool slowly for 1 hour.

Step 4: Chill the Cheesecake

1. Remove the cheesecake from the water bath and let it cool completely at room temperature.
2. Cover the pan with plastic wrap or aluminum foil and refrigerate for at least 6 hours, or overnight, to allow the flavors to develop and the texture to set.

Step 5: Make the Salted Caramel Sauce

1. In a medium saucepan, combine the granulated sugar and water over medium heat. Stir gently until the sugar dissolves, then stop stirring and let the mixture cook until it turns a deep amber color.
2. Remove the saucepan from the heat and carefully whisk in the warmed heavy cream. The mixture will bubble vigorously, so add the cream slowly.
3. Stir in the butter and flaky sea salt until smooth. Let the caramel sauce cool to room temperature before using.

Step 6: Decorate and Serve

1. Once the cheesecake is fully chilled, remove it from the springform pan and place it on a serving platter.
2. Pour the salted caramel sauce over the top, spreading it gently with a spoon or spatula.
3. Garnish with extra flaky sea salt and, if desired, crushed Biscoff cookies for added texture and presentation.
4. Slice and serve, enjoying the decadent combination of creamy cheesecake and salted caramel.