Prepare the Crust:

1. Make the Crust: In a medium bowl, combine the graham cracker crumbs, sugar, cinnamon, and melted butter. Stir until the mixture is well combined and resembles wet sand.
2. Press into Pan: Press the mixture into the bottom of a 9-inch springform pan, using the back of a spoon to pack it down evenly. Bake in a preheated oven at 350°F (175°C) for 10 minutes to set the crust. Remove from the oven and let it cool while you prepare the filling.

Prepare the Apple Filling:

3. Cook the Apples: Peel and chop the apples into small chunks. In a large skillet, melt the butter over medium heat. Add the apples, brown sugar, cinnamon, nutmeg, salt, and lemon juice. Cook, stirring occasionally, for about 5-7 minutes until the apples are softened and the mixture is caramelized. Set aside to cool.

Prepare the Cheesecake:

4. Mix the Cheesecake Filling: In a large mixing bowl, beat the softened cream cheese and granulated sugar until smooth and creamy. Add the vanilla extract, eggs (one at a time), sour cream, heavy cream, and flour. Beat until smooth and well combined.
5. Assemble the Cheesecake: Pour the cheesecake batter over the cooled crust in the springform pan. Smooth the top with a spatula.

Assemble the Dessert:

6. Add the Apples: Spoon the cooled apple filling evenly over the cheesecake batter, pressing them gently into the batter with a spoon.
7. Prepare the Crumble Topping: In a medium bowl, combine the rolled oats, flour, brown sugar, cinnamon, and salt. Add the cold cubed butter and mix with your fingers or a pastry cutter until the mixture resembles coarse crumbs.
8. Top with Crumble: Sprinkle the crumble topping evenly over the apples and cheesecake batter.

Bake and Cool:

9. Bake the Cheesecake: Bake the cheesecake in the preheated oven at 325°F (160°C) for about 1 hour 15 minutes, or until the center is set but slightly jiggly. The top should be golden brown and the crumble topping slightly crispy.
10. Cool and Chill: Let the cheesecake cool to room temperature for about 1 hour. Then, cover and refrigerate for at least 3-4 hours, or overnight, to fully set.