To make the dough, in a food processor, combine the confectioners’ sugar, butter, and vanilla extract and process until well mixed.
Add the egg yolks and process until blended. Add the flour and pulse several times. Do not worry if the dough does not form a ball.
Press the dough together and cover it with plastic wrap. Refrigerate for at least 2 hours or, even better, overnight.
On a lightly floured work surface, roll out the dough to an 11-inch circle about 1/8 inch thick. Wrap the dough around the rolling pin and unwind it over a 9-inch tart pan.
Press the dough deep down into the corners, letting 1/4 inch hang over the edges. Crimp the edges tightly, and then let the dough relax for 30 minutes in the refrigerator.
Preheat the oven to 375°F (190°C). Bake the tart shell until very lightly browned, about 10 minutes.