Make the crust: Combine graham cracker crumbs, brown sugar, and melted butter. Press into the bottom of the springform pan.
Prepare the cheesecake filling: Beat softened cream cheese and sugar until smooth. Add eggs, vanilla, and sour cream. Mix well.
Prepare the apple topping: Toss apple slices with sugar, cinnamon, nutmeg, and lemon juice. Set aside.
Make the crumble: Mix pecans, oats, flour, brown sugar, and cold butter. Rub together until crumbs form. Drizzle in maple syrup.
Assemble the cheesecake: Pour cheesecake filling over crust. Add apple slices and sprinkle with the pecan crumble.
Bake: Preheat oven to 325°F (163°C). Bake for 50-60 minutes until set.
Cool and serve: Let cheesecake cool, refrigerate for at least 2 hours before serving.