Preheat the oven to 160ºC (325ºF) and prepare a 9-inch springform pan by lining the bottom with parchment paper.

In a food processor, blend the digestive or graham crackers, ground cinnamon, nutmeg, and dark brown sugar until finely crushed. Add melted butter and pulse until combined. Press this mixture into the bottom of the prepared springform pan and bake for 10 minutes, then let it cool.

Wash and dice the apples, then toss with granulated sugar and ground cinnamon in a mixing bowl. Let mixture sit to absorb flavors.

Combine all-purpose flour, dark brown sugar, and cold butter in a separate bowl. Mix until it resembles coarse crumbs.

Beat the softened cream cheese until creamy, then gradually add granulated sugar. Mix in sour cream, cornstarch, and vanilla extract. Finally, beat in the eggs one at a time.

Pour the cheesecake filling over the cooled crust, spread evenly, then top with the apple mixture and sprinkle crumble topping.

Prepare a water bath by placing the filled springform pan into a larger dish and pouring hot water halfway up the sides. Bake for 1 hour and 20-30 minutes until the center jiggles slightly.

Turn off the oven, leave the door ajar, and let the cheesecake cool in the oven for 1 hour. Then refrigerate for at least 6 hours or overnight.