In a medium bowl, mix graham cracker crumbs and melted butter until evenly combined. Press mixture firmly into the bottom of an 8-inch springform pan. Chill for 15 minutes.
In a large bowl, beat cream cheese until smooth. Add powdered sugar and vanilla extract, mixing on medium speed until fully incorporated.
In a separate bowl, whip heavy cream until stiff peaks form. Fold half the whipped cream into the cream cheese mixture, then gently mix in the remaining cream until no streaks remain.
Spread the cheesecake filling evenly over the chilled crust. Cover and refrigerate for 4 hours or until firm.
Arrange mixed berries in a flag pattern (e.g., stars and stripes) on top of the chilled cheesecake. Serve immediately or store in the refrigerator.