Step 1

Whisk dry ingredients (flour and cornstarch) together and set aside.

Step 2

Cream butter and sugars with paddle attachment, on medium-low speed, until fluffy and pale in color (about 5 minutes).

Step 3

Add egg, extracts, and zest (if using) and mix on low speed until thoroughly combined. Scrape down the paddle with a spatula, and then continue to mix on low speed for another 30 seconds to ensure everything is fully incorporated.

Step 4

Add dry ingredients, all at once, and mix on low speed just until dough starts to come together and no dry bits remain. Do not overmix.

Step 5

Turn out dough onto cling wrap, wrap tightly, and refrigerate overnight (or at least 4 hours).

Step 6

Knead, roll, cut out cookies, and return to fridge or freezer until firm.  Leave a couple inches between cookies.

Step 7

Bake at 350° for ~15 minutes, turn pan, and bake for another 1-5 minutes until edges are starting to turn a golden brown.

Step 8

Remove from oven and allow to fully cool on cookie sheet before handling.