Using a stand mixer with a paddle attachment, cream the butter, sugar, and salt together on medium speed until smooth. Mix in ½ the beaten egg (save the other ½ for later) and scrape down the sides of the bowl with a rubber spatula. Add the flour and mix on low speed until incorporated.
On a lightly floured surface, shape dough into a disk ½-inch thick. Wrap well in plastic wrap and chill for at least 1 hour or overnight.
Place the disk of dough on a lightly floured surface and roll out ⅛-inch thick (about 11-inches in diameter), rolling from center to edge in all directions. Lift and rotate the dough occasionally, to make sure it doesn’t stick to the board, adding more flour if necessary. Lightly wrap the dough circle over the rolling pin and carefully unroll it over a 9-inch tart pan with a removable bottom.
When the dough has been lightly pressed into the proper shape, use the rolling pin to roll over all the metal edges, thus cutting the overhanging dough perfectly. Do not stretch the dough into the pan or else it will shrink when baking. If the dough tears at all, patch it with leftover bits of dough, pressing firmly. This is a very forgiving dough, unlike some others.
Additionally, you may re-roll your dough scraps and line a small 4-inch tartlet pan with more of the dough to make a BONUS cranberry curd tartlet!
Place the tart pan into the fridge for about 15 minutes or until firm. Meanwhile, preheat the oven to 325°F.
Prick the insides of the shell with a fork. Line the shell with a piece of parchment and fill with pie weights or dry beans. Bake for about 10 minutes, then remove the parchment paper filled with the weights and set them asides. If the dough has slouched in the tart pan at all you can carefully use the back of a small spoon to try and right the edges a bit. Then, lightly brush the inside of the tart with a bit of the leftover ½ beaten egg.
Bake for an additional 10 to 15 minutes or until the crust is set and the edges are faintly starting to brown. Let cool completely on a wire rack until ready to use. This baked shell will keep, well wrapped, in the refrigerator for 1 week, or in the freezer for 2 weeks.