For the crust: Process the flour, salt, shortening and butter in a food processor until you get the visual consistency of fine meal.
Place the fine meal into a bowl. With a fork make a hole in the meal. Pour the ice water in the hole and gently mix the water into the fine meal. Continue this process until the fine meal has the consistency of play dough.
Flour your board and rolling pin, and then roll out the dough. Divide the dough in half and roll out dough for a 2 crust 9-inch pie.
For the filling: If using frozen fruit, measure first, then thaw and drain fruit.
Preheat the oven to 350 degrees F.
Combine the flour, sugar and cinnamon, stir with fork. Place 1 crust into the pie pan. Spread 1/3 of the sugar mixture on the bottom and add fruit. Top the mixed berries with the rest of the sugar mixture. Wet the edges of the bottom crust by dipping your finger in the ice water and rubbing it around the edge of the crust. Place the top crust on the pie and gently press the top crust to the bottom. Trim with a knife and roll under. Press together with the thumb and forefinger to make a scalloped edge. With the knife, place 8 1/2-inch slits on the top of the pie. Bake for 45 minutes. When checking the doneness of the filling, insert a knife into the center of the pie. If there is little or no resistance, the pie is done.