Prepare the Crust: Preheat oven to 325°F (163°C). Combine graham cracker crumbs, sugar, and cinnamon in a bowl. Stir in melted butter until well combined. Press into a springform pan and bake for 10 minutes. Set aside to cool.

Make the Blackberry Swirl: Cook blackberries, sugar, and lemon juice in a saucepan over medium heat for 10 minutes. Stir in cornstarch slurry and cook for another 2 minutes. Strain to remove seeds and set aside.

Prepare the Filling: Beat cream cheese until smooth. Add sugar, sour cream, and vanilla extract, mixing until smooth. Add eggs one at a time, mixing gently until incorporated.

Assemble the Cheesecake: Pour half the filling over the crust, then spoon half the blackberry swirl and swirl gently with a knife. Repeat with the remaining filling and swirl. Tap the pan to remove air bubbles.

Bake: Bake at 325°F for 55–65 minutes, until the center is set but slightly jiggly. Turn off the oven, let the cheesecake cool for 1 hour.

Chill & Serve: Chill for at least 4 hours, preferably overnight. Remove from the springform pan and transfer to a platter. Serve and enjoy!