Place the flour, sugar, butter, and salt in a food processor and pulse until the mixture is just combined (somewhere between 5 and 10 pulses). Add 4 tablespoons water and pulse just until the dough holds together. If necessary, add more water, 1 tablespoon at a time, and pulse just until the dough begins to clump. Wrap the dough in waxed paper and refrigerate for 30 to 60 minutes.
Let the dough rest at room temperature for about 10 minutes. Butter and lightly flour an 11- or 10-inch round tart pan with a removable bottom.
Roll out the pastry dough on a lightly floured work surface to a circle slightly larger than the prepared tart pan. Transfer the dough to the pan, gently pressing the dough into the edges, and trim the edges by running a rolling pin over the top of the tart pan, using the edge of the pan as a cutting surface. Let the excess pastry fall away. Refrigerate for at least 30 minutes, until firm.
Preheat the oven to 400ºF (200ºC).
Prick the pastry base all over with the tines of a fork. Line the pastry with parchment paper and fill it with baking weights or dried beans. Bake for 15 minutes, then remove the parchment and weights, and bake for 10 to 15 minutes more, until golden. Let cool to room temperature.