Preheat your oven to 325°F (160°C).

In a food processor, blend the digestive biscuits, cinnamon and sugar until fine crumbs. Melt butter and combine with the crumb mixture. Press into the bottom of a 9-inch springform pan and bake for 10 minutes.

Prepare the cinnamon sugar topping by mixing dark brown sugar and cinnamon in a bowl.

Combine all-purpose flour and brown sugar in a bowl. Pour in melted butter and stir until coarse crumbs form.

Beat cream cheese until smooth. Gradually add sugar, sour cream, and cornstarch. Then, add eggs one at a time until smooth.

Pour half of the cheesecake batter over the cooled crust, sprinkle with cinnamon sugar, then spread the remaining batter. Finish with an even layer of crumble topping.

Place the springform pan into a larger pan filled with hot water. Bake for 1 hour and 15-20 minutes until the center is slightly wobbly.

Cool the cheesecake with the oven door ajar for about an hour. Then transfer to the refrigerator to chill for at least 6 hours.