In a large bowl, combine the flour, sugar, and salt.

Cut the cold, diced butter into the flour mixture using a pastry blender or your fingers.

Add the cold shortening and continue to cut in until the mixture resembles coarse crumbs.

In a separate small bowl, whisk together the beaten egg, vinegar, vanilla, and cold water.

Gradually add the wet ingredients to the dry ingredients, mixing until just combined.

If using an electric mixer, use the paddle attachment. Otherwise, mix with a spoon until the dough just comes together.

If there are dry crumbs at the bottom of the bowl, add a few drops of water to moisten them and incorporate them into the dough.

Form the dough into a disc and rub both sides with flour.

Place the dough in a zip-top bag and chill in the refrigerator for at least one hour before using.

Before rolling, sprinkle flour on a clean surface.

Roll out the dough to your desired thickness for your recipe.

Bake according to your specific recipe instructions.