Preparation

• 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.
• Place fresh blackberries into a food processor and puree until smooth. Strain the puree through a fine mesh sieve to remove seeds. Stir in ¼ cup sugar and 2 tablespoons water to sweeten and thin the puree slightly. Set aside.
• In a large bowl, beat the cream cheese and 1 cup granulated sugar on medium speed until smooth and fluffy. Add sour cream and vanilla extract, mixing until fully incorporated. Add eggs one at a time, beating well after each addition.
• Pour half of the cheesecake filling over the chilled crust. Drizzle half of the blackberry puree over the top and swirl gently. Repeat with remaining filling and puree.
• Preheat oven to 325°F (165°C). Bake for 55-65 minutes, until edges are set and center jiggles slightly. Turn off the oven and leave cheesecake inside with door slightly open for 10 minutes.
• Allow to cool to room temperature. Cover and refrigerate for at least 4 hours, preferably overnight. Before serving, garnish with fresh blackberries.