Mocha Cookie Bars

Preheat the oven to 350 degrees F (175 degrees C). Line an 8x8-inch square pan with parchment paper, ensuring enough overhang on all sides for easy removal. (5 minutes)

In a small bowl, combine instant espresso powder and strong brewed coffee. Stir until the espresso powder is completely dissolved, creating a concentrated coffee essence. (2 minutes)

In a separate bowl, whisk together all-purpose flour, unsweetened cocoa powder, cream of tartar, baking soda, salt, and 1/4 teaspoon of ground cinnamon. This ensures even distribution of the dry ingredients. Set aside. (3 minutes)

In a large mixing bowl, beat the softened unsalted butter, 1/2 cup of white sugar, and firmly packed brown sugar together using an electric mixer until the mixture is light and fluffy. This step is crucial for achieving a tender crumb. (5 minutes)

Add the espresso mixture, room temperature egg, and vanilla extract to the butter mixture. Beat until well combined, ensuring a smooth and emulsified batter. (3 minutes)

Gradually incorporate the flour mixture into the wet ingredients, mixing until a dough just begins to form. Be careful not to overmix, as this can result in tough bars. (4 minutes)

Using lightly floured hands, press the dough firmly and evenly into the prepared pan. This creates a uniform thickness for even baking. (2 minutes)

In a small bowl, whisk together the remaining 1 tablespoon of white sugar and 1/2 teaspoon of ground cinnamon. Sprinkle the sugar mixture evenly over the dough in the pan. (2 minutes)

Bake in the preheated oven until the center of the dough feels barely set, approximately 20 to 23 minutes. Keep a close eye on the bars to prevent over-baking; erring on the side of under-baking will result in a fudgier texture.

Allow the cookies to cool in the pan for 10 minutes. Then, using the overhanging parchment paper, gently lift the cookies out of the pan and transfer them to a wire rack to cool completely before cutting into bars. (10 minutes)