1. Cream softened or room temperature butter and powdered sugar.
2. Add egg and vanilla. Mix well.
3. In a separate bowl, mix together the dry ingredients: flour, baking soda, cream of tartar and sea salt.
4. Combine the dry ingredients to the wet ingredients and mix well.
5. Chill for at least one hour.
6. Preheat oven to 350 degrees F.
7. Roll out cookies and bake for 5-6 minutes, keeping an eye on them to prevent them from getting burnt. Once they are slightly turning brown, remove them. Allow to cool on the pan for a minute or so and then using a spatula, remove to a wire cooling rack to cool completely.