Preheat oven to 300°F and line a baking sheet with parchment paper. Set aside.

In a large mixing bowl with an electric mixer or in the bowl of your stand mixer, beat the butter and shortening on medium to high speed for 30 seconds. Add the sugar, baking soda, cream of tartar and salt and beat until well-combined, about 3 minutes, scraping down the sides as you go. Beat in the egg yolks one at a time, mixing well after each addition. Add the vanilla and almond extract and beat until incorporated..

Add the flour gradually until dough is combined and starts to pull away from the edges of the bowl and stick to the mixer.

Shape dough into 1 inch balls using a heaping teaspoon of dough. At this point you can freeze the dough up to 3 months or roll our on a floured surface to make cut out shapes.

Place balls or shapes of dough onto a prepared baking sheet about 2 inches apart.

Bake for 12-14 minutes or until edges are set, being careful to not let the edges brown. Cool the cookies on the baking sheet for 2 minutes then transfer to a wire rack to cool completely.

Decorate with frosting or store in an airtight container for up to 3 days or in the freezer for up to 3 months.