Combine The Flour, sugar, salt and baking powder in a mixing bowl. Cut the butter into six or eight pieces and distribute over the dry ingredients. Rub in the butter finely, using fingertips or pastry blender, until the mixture resembles a fine powder. Do Not Work The Mixture To The Point Where It Begins To Stick Together. Beat egg with a fork in a small bowl and stir into the flour-butter mixture: It will remain dry and crumbly. Turn the dough out into a buttered 10- to 11-inch removable-bottom tart pan or a 9-inch Pyrex pie pan. Distribute the crumbly mixture evenly around the bottom and side of the pan, pressing it into place with floured fingertips. As you press the dough into place, it will adhere together and line the pan. Avoid pressing the dough too hard or it will become thin in places. After pressing the dough into the pan, inspect the surface for any excessively thick or thin spots and press them even before proceeding. Slide dough into a plastic bag and chill several hours or overnight, or while preparing the filling.
Makes one 10- or 11-inch tart shell or 9-inch pie shell.
