Prepare the Cookie Crust:

• Preheat Oven: Preheat oven to 325°F (160°C) (conventional oven).
• Prepare Pan: Line the bottom of a 22cm (about 9-inch) springform pan with parchment paper. Grease the sides of the pan.
• Combine Dry Ingredients: In a medium bowl, combine the finely crushed digestive biscuits (or graham crackers), dark brown sugar, cinnamon, and nutmeg. Whisk to combine.
• Add Melted Butter: Pour the melted butter over the crumb mixture. Stir with a fork until the crumbs are evenly moistened.
• Press into Pan: Pour the crumb mixture into the prepared springform pan. Press the mixture firmly and evenly into the bottom and slightly up the sides of the pan. Use the bottom of a measuring cup or a glass to create a compact, even crust.
• Bake Crust: Bake the crust for 10 minutes.
• Cool Crust: Remove the crust from the oven and let it cool completely while you prepare the apples, crumble, and cheesecake filling.

2. Prepare the Apples and Crumble:

• Prepare Apples: Peel, core, and dice the apples into small cubes (about 1/4 – 1/2 inch). In a small bowl, toss the diced apples with the 1 tablespoon of granulated sugar and 1 teaspoon of ground cinnamon. Set aside. Note: The sugar will draw out some liquid from the apples; avoid adding this liquid to the cheesecake.
• Make Crumble: In a separate medium bowl, combine the flour and brown sugar. Cut in the cold butter using a pastry blender, fork, or your fingertips until the mixture resembles coarse crumbs. (Alternatively, you can use an electric mixer on low speed). Set aside.

3. Make the Cheesecake Filling:

• Preheat Oven: Preheat the oven to 320°F (160°C).
• Cream Cheese and Sugar: In a large bowl, using an electric mixer (stand mixer with paddle attachment or hand mixer) on low speed, beat the room-temperature cream cheese until completely smooth and creamy (about 1 minute). Gradually add the granulated sugar and continue to beat on low speed until well combined. Scrape down the sides of the bowl halfway through.
• Combine Sour Cream and Cornstarch: In a small bowl, whisk together the room-temperature sour cream and cornstarch until smooth.
• Add Sour Cream Mixture and Vanilla: Add the sour cream mixture and vanilla extract to the cream cheese mixture. Beat on low speed until just combined.
• Add Eggs: Add the room-temperature eggs one at a time, beating on low speed until just combined after each addition. Do not overmix. Scrape down the sides of the bowl as needed.

4. Assemble the Cheesecake:

• Pour Batter: Pour the cheesecake batter over the cooled crust in the springform pan.
• Add Apples: Gently distribute the cinnamon-sugar apples evenly over the top of the cheesecake batter. Drain off any excess liquid from the apples before adding them.
• Add Crumble: Sprinkle the prepared crumble topping evenly over the apples.

5. Prepare Water Bath:

• Wrap Pan: Wrap the outside of the springform pan tightly with a triple layer of heavy-duty aluminum foil. This will help prevent water from seeping into the cheesecake during baking.
• Place in Larger Pan: Place the wrapped springform pan inside a larger roasting pan (or a larger cake pan).
• Add Hot Water: Carefully pour hot (boiling) water into the roasting pan, filling it about ⅔ of the way up the sides of the foil-wrapped springform pan. This creates a water bath, which helps the cheesecake bake evenly and prevents cracking.

6. Bake: Bake in the preheated oven for 1 hour and 20-30 minutes, or until the edges of the cheesecake are set and the center has a slight jiggle.

7. Cool in Oven: Turn off the oven. Leave the oven door closed for 30 minutes. Then, crack open the oven door slightly and let the cheesecake continue to cool slowly in the oven for another 30 minutes. This gradual cooling process helps prevent cracking.

8. Cool and Chill: Remove the cheesecake from the oven and the water bath. Carefully remove the aluminum foil. Let the cheesecake cool completely to room temperature on a wire rack. Once at room temperature, cover the pan tightly with plastic wrap and refrigerate for at least 6 hours, or preferably overnight, to allow it to set completely.

Serving:

• Carefully remove the sides of the springform pan.
• Slice and serve the cheesecake chilled.