In a large bowl, mix the flour, sugar and salt together.
Add the cubes of cold butter and rub the mixture between your hands until you have a sand like texture.
Add the egg and gently knead the dough for a minute.
Refrigerate the dough for 1h or over night.
Roll the cold dough into the size and shape you want. Fill up the tart pan or pastry ring depending on what you are making.
Refrigerate for 1h or more.
Bake at 350F (180C) for 10 to 30 minutes depending on the size of your dessert, until golden brown.
Let cool completely before adding any filling.