Preparation

• Prepare the Crust: In a medium bowl, combine graham cracker crumbs, sugar, and ground cinnamon if using. Add melted butter and mix thoroughly until all crumbs are evenly coated. Press the mixture firmly into the bottom of a springform pan to form an even crust layer. Refrigerate the crust while you prepare the filling to help it set.
• Make the Blackberry Puree: Place fresh blackberries into a food processor and puree until smooth. Strain the puree through a fine mesh sieve to remove seeds, resulting in a silky texture. Stir in ¼ cup sugar and 2 tablespoons water to sweeten and thin the puree slightly. Set aside the puree for assembly.
• Make the Cheesecake Filling: In a large bowl, beat the cream cheese and 1 cup granulated sugar on medium speed until the mixture is smooth and fluffy with no lumps. Add the sour cream and vanilla extract, and mix until fully incorporated. Add the eggs, one at a time, beating well after each addition to ensure a creamy and uniform texture.
• Assemble the Cheesecake: Pour half of the cheesecake filling evenly over the chilled crust. Drizzle half of the blackberry puree over the top. Use a butter knife or skewer to gently swirl the puree into the cheesecake filling, creating a marbled effect. Repeat this layering and swirling process with the remaining cheesecake filling and blackberry puree.
• Bake the Cheesecake: Preheat your oven to 325°F (165°C). Bake the assembled cheesecake for 55-65 minutes, or until the edges are set and firm but the center still has a slight jiggle when gently shaken. Once baking time is complete, turn off the oven and leave the cheesecake inside with the door slightly open for 10 minutes to avoid cracking. Remove from oven and allow to cool to room temperature.
• Chill and Serve: Cover the cooled cheesecake and refrigerate for at least 4 hours, preferably overnight, to fully set and enhance flavors. Before serving, garnish the top with additional fresh blackberries for a fresh and attractive finish.