Into mixing bowl, sift together:

3 c. sifted flour
1 tbsp. sugar
3/4 tsp. salt
1/2 tsp. baking powder

Cut in 1 1/4 cups shortening until mixture resembles small peas.

Combine:

1 beaten egg
5 tbsp. water
1 tbsp. vinegar

Sprinkle 4 tablespoons of the mixture over flour mixture and mix lightly with fork. Add 4 more tablespoons egg mixture, continue mixing until pastry just holds together. Gather dough together with hands and press into ball. Wrap in waxed paper or clear plastic wrap; chill 15 minutes. Divide dough in half, roll out each half between pieces of clear plastic wrap.