01 - Preheat the oven to 350°F.
02 - Combine graham cracker crumbs, granulated sugar, and melted butter in a mixing bowl until evenly moistened.
03 - Firmly press the crumb mixture over the bottom and up the sides of a 9-inch pie dish. Bake for 8 to 10 minutes or until lightly golden, then remove and allow to cool completely.
04 - In a large bowl, beat cream cheese until smooth. Incorporate powdered sugar, sour cream, and vanilla extract, beating until fully combined and no lumps remain.
05 - In a separate bowl, whip the cold heavy cream with an electric mixer until stiff peaks form.
06 - Gently fold whipped cream into the cream cheese mixture until integrated and smooth. Divide the filling evenly into three portions.
07 - Leave one portion plain, tint one with red gel food coloring, and tint the last with blue gel food coloring, mixing each until colors are uniform.
08 - Randomly drop spoonfuls of each colored filling onto the cooled crust. Using a skewer or knife, gently swirl the colors to create a marbled appearance, taking care not to overmix.
09 - Level the top with a spatula and refrigerate for at least 2 hours, or until the filling is completely set.
10 - Before serving, pipe or spoon whipped cream over the pie and decorate with halved strawberries and blueberries as desired.