Preheat oven to 325°F (163°C). Line two 8-inch cake pans with parchment paper leaving enough overhang around the sides to easily lift shortbread out. (Tip: Parchment is used so you can easily remove the shortbread and not cut it while it’s in the pan. I like to use a square of parchment and I cut a 1-inch slit in the center of each side. This helps reduce the amount of creases when lined in the pan.)

Using a hand mixer or a stand mixer fitted with paddle attachment, beat the butter and granulated sugar together on medium-high speed until smooth and creamy, about 3 minutes. (Here’s a helpful tutorial if you need guidance on how to cream butter and sugar.) Scrape down the sides and up the bottom of the bowl as necessary. Add the vanilla and salt and beat until combined, about 1 minute. Scrape down the sides and up the bottom of the bowl as necessary. Add the flour and cornstarch and beat on low speed for 1 minute as the mixture begins to combine. Turn the mixer up to medium speed and beat for 1-3 minutes or until the dough clumps together. (It will eventually, just keep mixing it.) If you’re adding dry add-ins (see above), this is when you’ll add them.

Divide dough in half. If you want to be totally accurate, weigh the halves to make sure they’re even. Recipe makes almost 1.5 lbs of plain dough (will weigh more if you added add-ins). Press each half of dough into a prepared cake pan. You want it nice and compact in the pans. Sprinkle with optional coarse sugar. Dock the surface all over with a fork to prevent air bubbles.

Bake the shortbread for 28-30 minutes or until very lightly browned on top and around the edges.

Remove from the oven, place pans on a wire rack, and cool shortbread for 10-15 minutes. Carefully remove the shortbread from the pans by picking it up with the parchment paper on the sides. Cut each into 8 large, 12 medium, or 16 small wedges. You want to make sure you cut the shortbread while it’s still warm. Enjoy warm or cool shortbread completely on wire racks.

Cover and store shortbread at room temperature for up to 1 week. If you added a topping such as glaze, icing, buttercream, or melted chocolate, refrigerate after 2 days.