Cream together the butter and sugar in the bowl of an electric mixer fitted with a paddle on high speed until light and fluffy, about 3-5 minutes.
10 tablespoons unsalted butter, 3/4 cup powdered sugar
Lower the speed and add the egg, then the vanilla.
1 egg, 1/2 teaspoon vanilla extract
Mix together the flour and salt and gradually add to the bowl until just combined.
2 cups all purpose flour, 1/2 teaspoon salt
Wrap the dough in plastic wrap and place in the refrigerator to chill for at least an hour.
Just before removing the dough from the refrigerator, place the dried apricots in a bowl and cover with boiling (or very hot) water. Allow to sit and reconstitute for about 20 minutes.
2 cups dried apricots
Preheat oven to 350°F.
After the dough has chilled, roll it out to about 1/4-inch thick on a lightly floured surface. The dough will need to be rolled out slightly larger than the tart pan that you are using. It’s okay if the dough cracks around the edges. You can pinch it back together with your fingers, if needed.
Once rolled out, roll the dough up around the rolling pin, then carefully unroll it over the tart pan. Press the dough evenly into the pan so that the entire interior is covered in dough. Trim the excess from the edges.