It's from the The Farm Chicks in the Kitchen cookbook.  It makes four crusts, for two pies.
Everything I have made out of this cookbook has turned out really scrumptious.
"Grandma's Pie Dough"
4 cups all purpose flour
3/4 teaspoon salt
1 tablespoon sugar
1 3/4 c cold unsalted butter (3 1/2 sticks), cut into small pieces
1 tablespoon white vinegar
1 large egg
Combine the flour, salt, and sugar in a large bowl.  Cut in the butter 
using a pastry blender or your fingers until the mixture resembles 
coarse meal.  Whisk the vinegar, egg, and 1/2 cup of ice water
 together and mix into the flour mixture with your hands until just 
combined.  Transfer to a clean work surface, and gently press to form a 
dough.  Divide the dough into 4 equal parts.  Shape each into a ball, 
flatten slightly to form a disk, and wrap into plastic.  Chill for at 
least an hour.  Roll out as indicated in your recipe.
You could make the dough in a food processor, using the pulse feature, or in a Kitchen Aid stand mixer with the paddle attachment, or the good old fashioned method, with a pastry cutter, or two knives.  I've done all four methods.  They all work, just some are more work than others.
It's always nice to have "helpers" with the apples too -
Enjoy!

