Preheat the oven to 350°F and place a large baking sheet on the bottom rack. Lightly grease a 9″ tart pan and set aside. Remove the chilled shortbread dough from the refrigerator and roll out until about 1/4″ thick and until about an inch or an inch and a half larger around the tart pan. Transfer the dough into the tart pan, pressing down carefully to fit it snug into the bottom and sides. If the dough rips a little, don’t worry, you can always used your fingers to press it back together or you can take a piece off the edge and press it into place. Using a knife or a rolling pin, trim along the edge of the tart pan. With a fork, dock the bottom of the crust. Chill 15-30 minutes in the freezer until solid.