01 - Preheat oven to 350°F. Arrange your workspace with a 9-inch pie dish, mixing bowls, and utensils.
02 - Combine graham cracker crumbs, granulated sugar, and melted butter in a bowl. Mix until the texture resembles wet sand.
03 - Press the mixture evenly onto the bottom and sides of the pie dish. Bake for 8–10 minutes until fragrant and lightly golden. Remove from oven and allow to cool completely.
04 - Beat softened cream cheese in a large bowl until smooth. Incorporate powdered sugar, sour cream, and vanilla extract. Blend until uniform.
05 - In a separate bowl, whip cold heavy cream until stiff peaks form. Carefully fold the whipped cream into the cream cheese mixture, creating a light and airy texture.
06 - Portion the filling into three equal bowls. Leave one portion plain, tint one with red gel food coloring, and the third with blue gel food coloring. Stir each until fully colored.
07 - Drop alternating spoonfuls of each colored filling onto the cooled crust. Using a skewer or knife, gently swirl the colors for a marbled effect without overmixing.
08 - Level the surface and refrigerate for at least 2 hours, or until completely set.
09 - Prior to serving, top with whipped cream and arrange halved strawberries and whole blueberries as desired.