1-First Step: PREHEAT your oven to 350°F and lightly brush a 9-inch springform pan with melted butter for easy release. WASH and divide the blackberries and raspberries as needed, then PROCESS the chocolate wafer cookies in a food processor until they form fine crumbs. For vegan adaptations, use a gluten-free crust alternative like almond flour crumbs mixed with melted coconut oil; for low-calorie, reduce butter slightly and opt for a thinner crust.

2-Second Step: TRANSFER the crumbs to a bowl, ADD the 9 tablespoons of melted unsalted butter, and MIX thoroughly to combine. PRESS the mixture firmly into the bottom and up the sides of the prepared pan to form an even crust. BAKE for about 14 minutes until firm, then ALLOW it to cool completely while you REDUCE the oven temperature to 300°F. If making a gluten-free version, ensure your crumbs are from gluten-free sources to avoid any issues.

3-Third Step: In a blender, PUREE half of the blackberries with 1 teaspoon sugar and STRAIN through a fine sieve to remove seeds, setting the puree aside; REPEAT with half of the raspberries and another 1 teaspoon sugar. In a large bowl or stand mixer, BEAT the 3 packages of cream cheese until smooth, scraping down the sides as needed. For low-calorie options, SUBSTITUTE with low-fat cream cheese and beat carefully to maintain texture.

4-Fourth Step: ADD 1 cup sugar to the cream cheese and BEAT until smooth, then INCORPORATE the 1/2 cup sour cream and 2 teaspoons vanilla extract. ADD the 3 large eggs one at a time, beating on low speed until just combined to avoid overmixing. For vegan swaps, USE aquafaba in place of eggs and blend until the mixture holds together without curdling.

5-Fifth Step: SPOON half of the cream cheese mixture into the cooled crust, then DRIZZLE half of the blackberry and raspberry purees over the top. USE a toothpick or skewer to SWIRL them in for a marbled effect, creating that signature look of blackberry raspberry cheesecake. For dietary needs, if vegan, ensure purees are made with fruit only and adjust swirling to prevent mixing too much.

6-Sixth Step: ADD the remaining cream cheese mixture to the pan, DRIZZLE the rest of the purees on top, and SWIRL again gently. BAKE at 300°F for about 1 hour, or until the edges are set but the center jiggles slightly. TURN OFF the oven, PROP the door open, and LEAVE the cake inside for 1 hour to cool gradually, which helps prevent cracks for low-calorie versions, check doneness a bit earlier.

7-Seventh Step: REMOVE the cheesecake from the oven, LET it cool completely at room temperature, then REFRIGERATE for at least 4 hours or overnight for the best texture. Before serving, REMOVE the springform pan and GARNISH with the remaining blackberries, raspberries, and mint leaves. Total preparation time is around 20 minutes, with baking and cooling adding up to 1 hour 34 minutes plus chilling adapt by using faster vegan thickeners if needed.