Start by crushing graham crackers or your choice of cookies into fine crumbs using a food processor or a resealable bag and a rolling pin. Press these crumbs evenly into the bottom of a shallow tart pan, creating a firm base. Use the bottom of a flat glass to achieve an even layer, then chill the crust in the refrigerator for about 15 minutes to set while you make the filling.

In a large mixing bowl, beat the softened cream cheese using an electric mixer on medium speed until it becomes smooth and creamy, which should take about 2 minutes. Gradually fold in the whipped topping until the mixture is fully combined and lightened in texture.

Once the filling is fluffy and well-blended, divide it evenly into three separate bowls. Stir in your choice of berry purees or food coloring into two of the bowls for vibrant red and blue hues, keeping the third bowl plain for a marbled effect.

Spoon alternating dollops of the colored filling into the chilled crust, starting with the plain filling, followed by the blue, and then the red. Repeat until all filling is used, ensuring to periodically swirl the colors gently with a knife or toothpick.

Cover the pie with plastic wrap and refrigerate for at least 6 hours, or overnight if possible, to allow the filling to set properly.

Once chilled, carefully slice into your stunning 4th of July Swirl Pie and serve it to your guests. Garnish with fresh berries or a dollop of whipped cream if desired.