Prepare 12 3-4 inch pie tins by greasing with butter or shortening and lightly flouring. Preheat oven to 350°.
Place flour, salt, and butter in the bowl of a food processor*. Pulse until sandy. Add the yolk and pulse a few more times to combine. Add water 1 Tbs at a time and pulse until it just starts to come together.
Form dough into 2 disks, wrap in plastic wrap, and chill for at least 30 minutes.
Roll dough to ¼ thickness and cut into circles slightly larger than your tart tins. Gently lay circle into tin and press into sides. Prick bottom a few times with a fork, and chill in fridge for 15 min. Repeat for all remaining tins. Alternatively, you can use one large tart tin.
Bake for 20-25 minutes or until lightly golden. Let cool.