Ingredients:

  • 1/2 cup unsalted butter, softened
  • 3/4 cup granulated sugar
  • 1 large egg
  • 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
  • 2 tbsp ground cinnamon

Instructions:

  1. In a large bowl, beat the softened butter and 3/4 cup granulated sugar using a hand mixer on medium-high until the mixture is pale and fluffy (about 2 minutes).
  2. Add the egg and beat on medium until fully incorporated and smooth.
  3. In the same bowl, whisk together the flour, cream of tartar, baking soda, and salt.
  4. Mix on low speed just until the white streaks of flour disappear; do not over-mix.
  5. Preheat oven to 350°F (175°C) and line baking sheets with parchment paper.
  6. Scoop about 1 tablespoon of dough and roll it into a 1-inch ball.
  7. Roll the dough ball in the cinnamon-sugar mixture twice to create a concentrated outer layer.
  8. Place balls 2 inches apart on the baking sheet.
  9. Bake for 8–10 minutes until edges are set and slightly golden, but centers remain soft.