Preheat your oven to 325°F (160°C).

Prepare the crust by pulsing digestive biscuits, cinnamon, and sugar in a food processor to form fine crumbs. Melt the butter and mix with the crumbs. Press into a 9-inch springform pan. Bake for 10 minutes and set aside.

Mix dark brown sugar and cinnamon in a medium bowl for the cinnamon sugar mixture.

Combine all-purpose flour and dark brown sugar for the crumble topping and mix in melted butter until crumbly.

Mix cream cheese in a stand mixer until smooth. Gradually incorporate sugar, sour cream, and cornstarch, followed by eggs one at a time.

Layer half the cheesecake batter over the cooled crust, sprinkle half the cinnamon sugar mixture, then pour the remaining batter on top.

Sprinkle the crumble topping over the cheesecake.

Set up a water bath by placing the springform pan in a larger baking dish with hot water up to two-thirds of the pan's height.

Bake for 1 hour and 15-20 minutes or until slightly wobbly in the center.

Turn off the oven, leave the door ajar, and cool the cheesecake inside for an hour.

Chill the cheesecake in the refrigerator for at least 6 hours or overnight.