Add the butter and sugars to the bowl of a stand mixer (or a large bowl if using an electric hand mixer).
Beat until well-combined, about 3-4 minutes on medium.
Scrape down the sides of the bowl.
Mix in the vanilla extract, almond extract if using, and salt until combined.
Add egg yolk and mix in until combined.
Add the flour and stir in until just combined. Don't overmix.
Lightly flour your hands and form the dough into a ball.
Form the dough into a 1-inch thick disk.
Wrap tightly in plastic wrap, and chill for 30 minutes.
Preheat oven to 350F. Line cookie sheets with parchment paper or silicone baking mats. Set aside.
Unwrap the chilled dough and place on a lightly floured surface.
Roll the dough out to 1/4- or 1/3-inch thick. Thinner dough will give you a crispier cookie.
Cut out desired cookie shapes and transfer the cut-outs to the prepared baking sheet, spacing the cookies about 2 inches apart.
Recombine any scraps and continue cutting out shapes until you've used all of the dough.
Bake for 10-15 minutes. Depending on the size of the cookie cutter you use and how thick the dough is, you may need t to adjust the baking time. The cookies should just be beginning to turn light golden brown at the edges but shouldn't be browned.
Let the cookies cool on the baking sheet for 10 minutes.
Transfer to a wire cooling rack to finish cooling before frosting and decorating.
Notes
Butter - I use salted butter. If you're using unsalted butter, increase the salt by 1/4 teaspoon.
Brown sugar - I use light brown sugar.
Vanilla extract - The vanilla helps to give the cookies their flavor.
Almond extract - The almond extract gives the cookies a depth of flavor, but it doesn't make them taste like almond. Feel free to leave it out if you prefer.
Egg yolk - Just the yolk. You can save the white for another use.
All-purpose flour - It's important to properly measure the flour to avoid dry or heavy cookies. To properly measure it, either weigh the flour or sift/stir to break it up. Then lightly spoon into the measuring cup and level. Packing the flour will give you too much flour in the dough.