Preparation Steps

• In a stand mixer fitted with paddle attachment, cream together the softened butter, granulated sugar, and light brown sugar on medium-high speed for about 3 minutes until fluffy.
• Add the egg and vanilla extract, continuing to beat on medium-high speed until the mixture is light and fluffy, about 3 minutes.
• On low speed, add the all-purpose flour, baking soda, cream of tartar, and optional salt, mixing just until combined, about 1 minute.
• Form 14 equal-sized dough balls (about 2 heaping tablespoons each) using a cookie scoop or your hands, and flatten each slightly.
• Place dough balls on a plate, cover with plastic wrap, and refrigerate for at least 1 hour and up to 5 days. Do not bake unchilled dough to prevent spreading.
• Preheat oven to 350°F. Line a baking sheet with a Silpat or spray it with cooking spray.
• In a small bowl, mix together the 0.25 cup sugar and 2 teaspoons cinnamon for coating.
• Roll each chilled dough ball in the cinnamon sugar mixture until fully coated.
• Place coated dough balls on the prepared baking sheet at least 2 inches apart and bake for about 9 minutes until the edges are set but the centers remain soft and glossy.
• Allow cookies to cool on the baking sheet for about 10 minutes before serving.