Mix the butter and powdered sugar in the bowl of your standing mixer or in a large bowl. Add the egg, vanilla, and almond extract. Mix until well combined.
In a separate bowl, combine the flour, baking soda, and cream of tartar.
Add the dry ingredients to the butter and sugar mixture and mix to combine.
Divide the dough into two parts and wrap in plastic. Chill in the refrigerator for at least two hours before rolling it out.
Make the Buttercream
While the cookie dough is chilling, go ahead and make the buttercream icing.
In the bowl of your mixer, or in a medium mixing bowl, mix the softened butter until it is light and fluffy.
Stop the mixer and through a sifter, add the confectioner's sugar. Then add the vanilla and almond extracts, and 2 tablespoon of milk. Starting on the lowest setting, mix the icing together.
Once combined, check your consistency and add more milk if needed. Scrape the sides of the bowl and turn the mixer up to medium speed. Beat the icing on medium for 2-3 minutes or until it is nice and fluffy.
Reserve the icing until you are ready to decorate your cookies.
Preparing the Cookies for Baking
Preheat oven to 375° Line a half sheet pan with parchment paper.
Remove one ball of dough from the refrigerator. On a lightly floured surface, roll the dough until it is about ⅛ of an inch thick. Cut into your desired shapes.
Bake for 7 to 8 minutes until cookies are barely brown on the edges. If you prefer your cookies crunchier, you can bake for a bit longer.
Remove cookies from the oven and allow them to rest for a few minutes before transferring them to a cooling rack to cool completely
Once the cookies are cool, have fun decorating. You can spread or pipe on the icing and cover with your favorite sprinkles. Enjoy!