To make Food Network's Country Blueberry Pie using frozen berries, first thaw 3 cups of frozen blueberries, and rinse under cold water. Drain the berries in a colander while preparing the rest of the filling.
To make the pie filling, combine 3/4 cup sugar, 2 tablespoons cornstarch, 1/2 teaspoon cinnamon and 1/2 cup water in a saucepan. Boil the filling, stirring constantly, until the sauce thickens. Set the sauce aside to cool. Once the sauce is cool, stir in the thawed, drained berries and 1 tablespoon fresh lemon juice.
To make the dough, mix 2 cups flour with 1 tablespoon granulated sugar and 1 teaspoon salt. Cut 3/4 cups of shortening into the flour mixture. In a separate bowl, whisk together 1 egg, 2 tablespoons water and 1/2 tablespoon white vinegar. Add the egg mixture to the flour mixture slowly, stirring with a fork. Turn the mixture out onto a floured cutting board, and knead to combine until a dough forms. Divide the ball of dough in half.
Roll out half of the dough, and line the bottom of a 9-inch pie plate with the crust. Pour the cooled filling into the lined pie plate. Roll out the top crust so that it completely covers the top of the pie. Cover the pie with the crust, and pinch the rim to seal. Cut vents in the top crust, and sprinkle lightly with sugar if desired. Place the pie plate onto a rimmed baking sheet, and bake at 425 degrees Fahrenheit for 20 minutes. Reduce the heat to 350 degrees Fahrenheit, and bake for an additional 20 to 25 minutes.