Preheat oven to 400F. Line a baking sheet with parchment paper and set aside.

Cream together shortening and sugar until well-combined (I use a stand mixer, but you can use a hand mixer as well).

Add eggs, one at a time, mixing well after each addition.

In a medium bowl, whisk flour, cream of tartar, baking soda, and salt together.

Gradually add dry ingredients to the wet ingredients, mixing on low speed just until combined.

Roll dough into balls about the size of ping pong balls or small walnuts (I use a small cookie scoop, then roll the dough in my hands). Roll each ball of dough in the cinnamon and sugar mixture to coat.

Place dough balls about 2 inches apart on prepared baking sheet.

Bake 8-10 minutes, until edges are very slightly golden brown and centers are still soft (8 minutes will result in softer, chewier cookies and 10 minutes will result in crispier cookies).

Let cookies cool on the pan for about 5 minutes, then transfer to a wire rack to cool completely.