In a mixing bowl, combine flour and sugar. Add cold butter and mix until crumbly.

Gradually add ice water until the dough comes together. Shape into a disk, wrap in plastic, and refrigerate for 30 minutes.

Preheat the oven to 375?F (190?C). Roll out the dough and fit it into a 9-inch pie pan.

In a bowl, combine strawberries, blueberries, raspberries, sugar, cornstarch, and vanilla extract. Mix gently.

Pour the fruit mixture into the prepared pie crust, arranging the strawberries and blueberries to create a flag design.

Bake in the preheated oven for 45 minutes or until the crust is golden and the filling is bubbly.

Allow to cool before serving. Enjoy your patriotic Flag Pie!