Preheat your oven to 325°F (163°C). Grease a 9-inch springform pan and in a mixing bowl, combine graham cracker crumbs with granulated sugar and melted butter. Press the crumb mixture evenly into the bottom of the pan. Bake for 10 minutes until lightly golden, then allow it to cool completely.

In a large mixing bowl, beat well-softened cream cheese until smooth and creamy. Gradually mix in granulated sugar until fully combined. Add eggs one at a time, incorporating them fully before adding vanilla extract and sour cream. Mix until everything is just combined, then pour this filling over your cooled graham cracker crust.

Prepare a water bath by placing the springform pan inside a larger baking pan filled with hot water. Bake the cheesecake for 55-65 minutes, or until the center is slightly jiggly but the edges are set. Turn off the oven, crack the door ajar, and let it cool in the oven for 1 hour.

Remove the cheesecake from the water bath and allow it to cool to room temperature. Cover it loosely with plastic wrap and refrigerate for at least 4 hours, or overnight to set completely.

In a skillet over medium heat, melt unsalted butter, then add diced apples along with brown sugar, ground cinnamon, and ground nutmeg. Cook while stirring occasionally for about 8 minutes until the apples are tender. Remove from heat and set aside.

In a medium saucepan, heat granulated sugar over medium heat, stirring gently until it melts and turns a deep amber color. Quickly add in unsalted butter and whisk until fully incorporated. Carefully whisk in heavy cream, allow boiling for 1 minute, then remove from heat and stir in sea salt.

Once the cheesecake has chilled thoroughly, gently remove it from the springform pan. Top with the warm apple mixture, spreading it evenly over the surface. Drizzle the salted caramel sauce generously over the apples.