Ingredients
Method
Prepare the Oven and Pan
- Preheat your oven to 350 degrees Fahrenheit. Line a 9x13-inch baking dish with parchment paper, leaving some overhang for easy lifting.
Mix the Dry Ingredients
- In a medium bowl, whisk together the flour, baking soda, cream of tartar, and salt. Set aside.
Cream Butter and Sugar
- In a large mixing bowl, beat the softened butter and 1 1/2 cups of granulated sugar together until light and fluffy, about 2 to 3 minutes with an electric mixer.
Add Egg and Vanilla
- Beat in the egg and vanilla extract until fully combined, scraping down the sides of the bowl as needed.
Combine Wet and Dry Mixtures
- Gradually add the dry ingredients to the wet mixture, mixing on low speed just until no streaks of flour remain. Do not overmix.
Spread the Dough
- Transfer the dough to the prepared pan and spread it evenly to the edges using a spatula or your fingertips.
Add Cinnamon Sugar Topping
- In a small bowl, stir together the remaining 1/2 cup of granulated sugar and the cinnamon. Sprinkle this mixture evenly over the dough.
Bake the Bars
- Bake for 20 to 25 minutes, until the edges are lightly golden and a toothpick inserted into the center comes out clean. Let the bars cool completely in the pan on a wire rack.
Slice and Serve
- Once cool, lift the bars out using the parchment paper. Cut into 24 squares and serve at room temperature.
Nutrition
Notes
For a softer bar, reduce baking time by 2 minutes. If you don't have cream of tartar, substitute with 2 teaspoons of lemon juice or white vinegar added to the butter mixture. Store leftover bars in an airtight container at room temperature for up to 5 days. For a make-ahead option, prepare the dough, press it into the pan, cover tightly, and refrigerate for up to 24 hours before adding the topping and baking. Avoid overmixing the dough to keep the bars tender. Serve with a cold glass of milk or a scoop of vanilla ice cream for a decadent dessert.