In a medium bowl, whisk flour, salt, and sugar together until well-combined.

Add in the cold vegetable shortening and cut in with a fork or pastry cutter, incorporating the pieces of shortening into the dry mixture until it's crumbly and the shortening pieces are about the size of little peas or pebbles.

Add in the vinegar. Then slowly add in the non-dairy milk (I prefer to use almond milk), about 1 Tablespoon at a time. After each add, use your hands to quickly incorporate the liquid into the flour mixture, creating a shaggy dough. You want to work as quickly as possible so you don't add too much warmth from your hands. Keeping all ingredients cold will keep the shortening in small "pebbles" allowing for a flaky and tender crust. Once the dough has come together, form it into a round disk.

Sprinkle flour on a clean tea towel or dish cloth and place disk of dough on top. Sprinkle with a small amount of flour and roll gently with a rolling pin. Roll in all directions until your dough is about 1/8" thick and is slightly larger than your pie plate.

With the help of the tea towel, carefully pick up the pie crust and lay it into your pie plate. Trim the edges and if you'd like, make a pretty scalloped edge.

If your recipe calls for a pre-baked pie crust, bake for 17-20 minutes at 400 degrees F. 

Otherwise, fill your pie crust as the recipe calls for and bake according to the instructions.