In a large bowl, whisk together the flour and salt. Add the shortening and butter; use a pastry blender to cut the butter and shortening into the flour until the mixture resembles a coarse meal with a few pea-sized pieces of butter/shortening.
Sprinkle the vinegar and water over the mixture. Mix with a fork, just until the mixture holds together when squeezed in your palm - it will still look crumbly in the bowl. If your home is particularly dry, you may need to add a bit more water, 1/2 tablespoon at a time, until you reach the correct consistency.
Turn the dough out onto a floured board. Pat into a circle; cut in half. Place one half in the refrigerator while you roll out the second to fit your pie plate. Remove second half from fridge and roll out to top the pie, baking according to your recipe.
If totally blind baking, bake at 450 degrees for 8-10 minutes or just until golden.
Notes
For one single-crust pie, either halve the recipe or use half and freeze the other half for later.Makes 1 double-crust or 2 single-crust 9-or 10-inch pies.