In a large bowl, sift together flour, baking soda, baking powder & salt. Cut in white & yellow Crisco shortening until it resembles small peas. In a 1 cup measure, place egg & vinegar; combine. Add enough COLD water to fill cup. Pour all at once over flour mixture, mixing quickly, until dough pulls away from sides of bowl. This should only take a couple of minutes; DO NOT OVER MIX PASTRY.