Sift together flour and baking powder in large bowl. Cut margarine and shortening into dry ingredients, until mixture is the size of peas. In measuring cup, beat egg well. Add vinegar and enough water to measure 1 cup . Combine with flour mixture. Minimal mixing. If pastry is too soft, add a little more flour to make desired consistency. Roll out on lightly floured pastry board and line greased pie plate. Yield: 4 two crust pies.