Ingredients:

  • 1 cup (2 sticks) Unsalted Butter, softened
  • 1 1/4 cups Granulated Sugar (for the dough)
  • 2 Large Eggs, room temperature
  • 1 teaspoon Vanilla Extract
  • 2 3/4 cups All-Purpose Flour
  • 2 teaspoons Cream of Tartar
  • 1 teaspoon Baking Soda
  • 1/2 teaspoon Fine Sea Salt
  • 1/4 cup Granulated Sugar (for the topping)
  • 2 teaspoons Ground Cinnamon (for the topping)

Instructions:

  1. Preheat your oven to 350°F (175°C). Line the 8x8 inch baking pan with parchment paper, allowing some overhang for easy removal.
  2. In a medium bowl, whisk together the flour, cream of tartar, baking soda, and salt until thoroughly combined. Set aside.
  3. In the bowl of a stand mixer, cream the softened butter and the 1 1/4 cups of granulated sugar on medium speed. Beat for 3–4 minutes until the mixture is light, fluffy, and noticeably paler.
  4. Beat in the eggs, one at a time, ensuring each is fully incorporated. Scrape down the bowl. Mix in the vanilla extract.
  5. Reduce the mixer speed to low. Gradually add the whisked dry ingredients to the wet mixture. Mix only until just combined, ensuring no streaks of flour remain.
  6. In a small, shallow bowl, combine the 1/4 cup of sugar and 2 teaspoons of cinnamon for the topping.
  7. Transfer the dough to the prepared 8x8 pan. Using a rubber spatula or lightly oiled hands, press the dough evenly into the bottom of the pan, reaching all four corners.
  8. Generously sprinkle the cinnamon-sugar topping evenly over the top of the pressed dough.
  9. Bake for 30 to 35 minutes. The bars are ready when the edges are lightly golden brown and the center looks set but still slightly soft (a toothpick should come out with moist crumbs attached).
  10. Remove the pan from the oven and place it on a wire rack. Let the bars cool completely—at least 2 hours—before lifting the slab out using the parchment overhang and slicing into 16 squares.