In the bowl of a food processor, blitz together flour, sugar, and salt briefly to combine.
Cut the butter into 1 tablespoon pieces (approximately). With the food processor on low, drop the tablespoons of butter into the flour mixture one at a time. Wait about 3-5 seconds before adding in the next one to make sure the butter does not clump together.
Once all the butter has been added, pour in the vanilla and blitz for another 10-15 seconds, or until the crust resembles wet sand.
Let the crust rest in the bowl for about 20 minutes. While it is resting, preheat the oven to 375 degrees.
Press the crust into the bottom of a 9" tart pan (with a removable bottom). Make sure the crust goes all the way up the sides of the tart pan. It may be helpful to use a spoon or the back of a measuring cup to make sure the crust is packed tightly.
Place a piece of parchment paper over the crust, and fill the whole tart with baking beads or dry beans. This will prevent the crust from bubbling up or sliding down the sides of the pan. Bake for 20-22 minutes. You will know it is done when the tart shell is no longer shiny but is not yet brown.
When the tart crust is done, remove it from the oven and let it come to room temperature. If you have not yet made the lemon curd, wrap the tart shell in plastic wrap (still in the pan) and set aside until you are ready to assemble.