Ingredients:

  • 3/4 cup unsalted butter, softened
  • 3/4 cup granulated sugar
  • 1/4 cup brown sugar, packed
  • 1 large egg, room temperature
  • 1 tsp vanilla extract
  • 2 3/4 cups all-purpose flour
  • 2 tsp cream of tartar
  • 1 tsp baking soda
  • 1/2 tsp salt
  • 1/4 cup granulated sugar (for coating)
  • 1 tbsp ground cinnamon

Instructions:

  1. Cream together the softened butter, granulated sugar, and brown sugar using a mixer on medium-high until pale and fluffy (about 2-3 minutes). Add the egg and vanilla extract, beating until fully incorporated.
  2. In a separate bowl, whisk together the flour, cream of tartar, baking soda, and salt. Gradually add the dry ingredients to the wet ingredients on low speed, mixing just until flour streaks disappear.
  3. Scoop approximately 1.5 tablespoons of dough and roll into a 1-inch ball. Roll the ball in the cinnamon-sugar mixture until completely coated. Place on a parchment-lined sheet, spacing them 2 inches apart.
  4. Bake at 350°F (175°C) for 8 to 10 minutes. Remove from oven when edges are set and slightly golden, but centers still look soft. Let rest on the hot pan for 5 minutes before transferring to a wire rack.