1tablespoonvanilla bean paste or pure vanilla extract
⅓cupsrice flourif you don't have it, all-purpose will do
Preheat the oven to 300°F/148°C and grease a 9-inch removable bottom tart pan.
Using a food processor or mixer fitted with the paddle attachment, beat the butter, sugar, vanilla, and brown sugar vigorously until pale and fluffy, about 3 minutes. It's an important step to beat the butter and sugar well together when making shortbread, as this ensures the shortbread is light, crisp, and holds together.
In a separate bowl, sift the flour and salt. Add it to the butter mixture and mix until blended (forming large clumps).
Transfer the mixture to the pan and press it evenly around the base and sides. Use a fork to dock the bottom of the dough all over.
Cover with plastic wrap and allow the dough to rest for at least 30 minutes.
If using a filling that needs to bake in the crust, partially bake the crust for 15 minutes, then fill and bake as directed. If you're using it for a shell, bake for 45 minutes or until the edges are lightly browned.
Cool completely in the pan on a cooling rack before pressing the bottom of the pan up through the middle and gently remove it from the pan before filling.
If you don't have a tart pan, this recipe can be used using an 8" (20 cm) or 9" (23 cm) square pan or baking dish, pie plate, or a springform pan. Using an 8-inch pan will result in a thicker crust. You can also use it for tartlets by using a mini tart pan or muffin pan.
Use room temperature softened butter - Butter that is too hard won't easily incorporate into the sugar, which is the key to a tender shortbread.
Beat your butter and sugar together for a good 3-4 minutes for the best possible results. At this stage, you can't overmix, so when in doubt, beat it another minute.
For an even lighter texture, sift the dry ingredients together before adding them to the creamed butter and sugar.
Flour your hands before pressing the dough into the pan to keep it from sticking to your hands.