01 - Preheat oven to 350°F (175°C).
02 - Combine graham cracker crumbs, granulated sugar, and melted butter in a mixing bowl. Press mixture evenly onto the bottom and up the sides of a 9-inch pie dish.
03 - Bake crust for 8 to 10 minutes until lightly golden. Remove from the oven and cool completely.
04 - In a large mixing bowl, beat softened cream cheese until smooth. Add powdered sugar, sour cream, and vanilla extract. Beat until well combined and smooth.
05 - In a separate mixing bowl, whip cold heavy whipping cream to stiff peaks.
06 - Gently fold the whipped cream into the cream cheese mixture until fully incorporated. Divide the filling evenly into three portions.
07 - Leave one portion plain for the white. Tint one with red gel food coloring and the other with blue gel food coloring, mixing each until color is even.
08 - Drop spoonfuls of each colored filling randomly onto the cooled crust. Using a skewer or knife, gently swirl the colors together for a marbled effect without overmixing.
09 - Smooth the surface of the filling. Refrigerate pie for at least 2 hours, or until fully set.
10 - Before serving, top with whipped cream and arrange fresh strawberries and blueberries as desired.