Spray or butter tart pan well so your shortbread comes out easy after baking. See above for some alternative pans you can use if you do not have a tart pan.
If you are using a tart pan, place the tart pan on top of another pan so butter doesn't drip out on to your oven when baking.
In a large bowl, using an electric mixer, combine the butter, sugar (brown and white) and beat until smooth, about 2 minutes.
1 ½ cups unsalted butter, ½ cup light brown sugar, ½ cup granulated white sugar
Next, add your vanilla and salt and mix that in.
1 teaspoons vanilla extract, 1 teaspoon kosher salt
Now, add flour into the butter mixture and mix on low-speed until the mixture starts to form a ball .
3 ½ cups all-purpose flour
Divide your dough in half and wrap up one half and place in the refrigerator until later. Press the other half of the dough into the bottom of the prepared pan to form the bottom crust.
Bake the crust until it is just beginning to turn light brown, around 20 minutes.
Remove the pan from the oven and let cool for a few minutes.
Place your preserves over on your shortbread crust and spread evenly.
10 oz jar of berry jam or preserves
Now, take your reserved half of the shortbread out of the refrigerator and crumble the dough over the preserves to make your crumbled topping, being careful to not have really large pieces.
Return the pan to the oven and continue baking for another 30 minutes or so until the crisp turns golden in color. Transfer to a wire rack and let cool completely.
Once cooled, your can slice up your tart (or bars if using a rectangular pan) and serve!