Preheat your oven to 325°F (160°C). In a mixing bowl, combine crushed digestive biscuits, cinnamon, sugar, and melted butter until well blended. Press this mixture into the bottom of a 9-inch springform pan to form the crust. Bake for 10 minutes until lightly golden, then let cool.

In a small bowl, mix dark brown sugar and cinnamon for the cinnamon sugar layer. Set aside.

Combine all-purpose flour and dark brown sugar in a separate bowl. Pour in melted butter and mix until crumbly. Set aside.

Using a stand mixer, beat cream cheese until smooth. Gradually add sugar, then mix in sour cream and cornstarch. Add eggs one at a time, ensuring a smooth batter.

Pour half of the cheesecake batter over cooled crust. Sprinkle half of the cinnamon sugar mixture, then pour remaining batter and top with crumble.

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

Turn off the oven, crack the door for 1 hour to cool. Transfer to the refrigerator and chill for at least 6 hours, preferably overnight.

Carefully remove sides of the springform pan, slice, and serve with coffee.