1. Preheat your oven to 350°F (180°C, or 160°C fan-forced). Wrap the outside of a 9-inch springform pan in tin foil 3-4 times to cover all seams and lightly grease the inside with non-stick spray.

2. In a bowl, mix graham crumbs, brown sugar, and cinnamon. Stir in melted butter until evenly combined. Press this mixture firmly into the pan’s bottom and halfway up the sides. Bake for 8-10 minutes, then remove and keep the oven on.

3. Peel, core, and thinly slice apples. Toss them with brown sugar and cinnamon, then refrigerate until needed.

4. Combine flour, brown sugar, and cinnamon in a medium bowl. Stir in oats, then mix in melted butter until mixture resembles damp sand and clumps when pressed.

5. In a large bowl, beat cream cheese with granulated and brown sugar until smooth. Mix in cornstarch and cinnamon, followed by sour cream and vanilla, scraping bowl as needed. Add eggs one at a time, mixing just until incorporated, ensuring no pieces remain visible.

6. Pour the cheesecake batter over the crust in the foil-wrapped pan and smooth the top. Evenly layer the sliced apples on top, avoiding any juice. Sprinkle the oatmeal crumble evenly over the apples.

7. Place the springform pan inside a large roasting pan. Pour boiling water into the roasting pan to come about 1 inch up the sides of the springform pan. Carefully place in the oven and bake for 50-60 minutes, until the cheesecake has a very slight wobble when gently shaken.

8. Remove cheesecake from oven and allow to cool in the roasting pan to room temperature. Once cooled, remove from water bath, cover with foil, and refrigerate for at least 6 hours or overnight to set fully.

9. Before serving, run a sharp knife around the edge to loosen, then unclamp the springform pan ring. Slice with a thin, sharp knife all the way through the crust. Optionally, drizzle pieces with salted caramel sauce for extra flavor.