Sift flour and salt together. If you choose not to sift the flour, use a tablespoon to heap the flour loosely into the measuring cup from the flour bag. Avoid compressing the flour to keep it aerated.
Take out 1/3 cup of the flour-salt mixture and place it into a new mixing bowl.
Add the water to the 1/3 cup of flour-salt mixture. Stir the water into the flour-salt mixture until smooth or the lumps are minimal. You should have a flour-salt-water slurry.
Cut the butter (or shortening) into the remaining flour-salt mixture. Use two butter knives to cut or a pastry blender to avoid overheating the butter.
Add the flour-salt-water slurry into the flour-butter mixture one spoonful at a time. Mix it with a fork until the dough can be shaped into a ball. Avoid packing the flour. Avoid touching the dough with your hands.
Cut the ball of dough into half.
Roll each crust into a circular shape. Push from the center outwards. Check the dough continues to move as you roll it out. If it starts to stick, add more flour underneath and to the rolling pin. Or cover with parchment paper or plastic wrap to avoid the dough sticking the rolling pin.
Lay the pie crust on the pie pan. Cut away the excess crust. Save it for decorations like lattice, hearts, or leaves. Put the pie pan and crust into the fridge for at least 15 minutes [timer minutes=15][/timer]to give the crust a chance to cool down and harden before filling and baking.
Bake at 425º F for 12-15 minutes if baking blind. I suggest dried beans or raw rice to weigh down your crust if you don't have pie weights.
Or follow your pie recipe's instructions for how to bake. For a single crust with a custard filling like lemon tart, prick the dough thoroughly with a fork before putting in the oven.