Using a stand mixer or hand mixer, beat butter, sugar, eggs, vanilla until smooth and creamy.
Whisk together flour, baking soda, and cream of tartar.
Slowly add the flour mixture to the egg and sugar mixture and beat until it comes together.
Place the mixing bowl into the refrigerator and chill the dough for 30-60 minutes.
While the dough is chilling, mix the cinnamon and sugar and set it aside.
Preheat the oven to 350°.Use a cookie scoop to scoop each cookie so they are all the same size.
Roll each ball in the cinnamon sugar and place it on the cookie sheet.
Slightly flatten each cookie with the palm of our hand.
Arrange 5 almond slivers on each cookie to look like a sand dollar.
Bake for 12 minutes.
Cool for 10 minutes before transferring them to a cooling rack.