Preheat your oven to 350°F (175°C). In a medium bowl, combine graham cracker crumbs, melted butter, and granulated sugar. Mix until well combined. Press the mixture firmly into the bottom of a 9-inch springform pan to form the crust. Bake for 10 minutes, then remove from the oven and let cool.

In a large mixing bowl, beat the softened cream cheese with an electric mixer until smooth and creamy. Gradually add the powdered sugar and vanilla extract, mixing until well combined.

In a separate bowl, whip the heavy cream until stiff peaks form. Gently fold the whipped cream into the cream cheese mixture until fully incorporated.

In a small bowl, toss the diced peaches and mixed berries with lemon juice. Gently fold the fruit into the cheesecake mixture.

Pour the cheesecake filling over the cooled crust in the springform pan, spreading it evenly. Cover and refrigerate for at least 4 hours, or overnight for best results.

Once set, carefully remove the sides of the springform pan. Slice the cheesecake and serve chilled, garnished with fresh mint leaves if desired.