mix together: butter, the 1/2 cup of sugar, and brown sugar. Mix for about 3 minutes.
Add egg, vanilla and beat till fluffy (about 5 minutes)
Add flour, baking soda, cream of tartar and salt. Mix for about a minute on a low speed.
Form about 14-15 cookie balls on a plate and plastic wrap it. Place in the refrigerator for at least an hour before baking…or up to 5 days…. well wrapped.
When you’re ready to bake the cookies, pre-heat oven to 350° and prepare the 1/4 cup of sugar and cinnamon by mixing them together in a small bowl. (I lined the cookie sheet with parchment paper) Roll the cookie balls in the cinnamon sugar and put the balls on a cookie sheet. You don’t need to flatten the cookie balls down. They spread out nicely. Leave about a 2 inch space between each cookie. Bake in pre-heated oven for 9-10 minutes.
When you take the cookies out, leave them on the cookie sheet for at least 10 minutes.