In a large bowl whisk together the flour, salt, brown sugar and baking powder.
With a pastry cutter, cut the shortening into the flour until the mixture is like coarse sand.
Then in a separate bowl mix together the water and vinegar. Then add the egg and mix thoroughly.
Gradually add the water/vinegar/egg mixture to the dry ingredients, mixing with a fork. You don’t have to use all the liquid if the dough seems too wet. Then use your hands to form a large ball of dough.
Chill 1 hour.
Separate the ball of dough into 4 even pieces, and shape each piece into a disc (this shape makes it much easier to roll out the dough). At this point, you can wrap 2 of the discs in plastic wrap and freeze them for later.
When you’re ready to make pie, use a rolling pin to roll out the dough. I like to place the dough on a piece of parchment paper lightly dusted with flour. This makes it easy to transfer the dough to a pie plate.