1-First Step: Prepare your pan and oven. Preheat your oven to 350°F (175°C). While the oven heats, fully line an 8×8-inch baking pan with parchment paper. Ensure the paper comes up the sides of the pan to create handles for easy removal later. This step is crucial for preventing the bars from sticking and making cleanup a breeze.

2-Second Step: Mix your dry ingredients. In a medium bowl, whisk together the all-purpose flour, cornstarch, baking soda, and salt until well combined. Set this mixture aside while you prepare the wet ingredients. This ensures the leavening agents are evenly distributed throughout the flour for consistent rising.

3-Third Step: Prepare the sugar and butter mixture. In a large bowl, whisk the melted butter with both the light brown sugar and granulated sugar. Continue whisking until the mixture becomes somewhat thick and well combined. This process helps dissolve the sugars and begins to incorporate air into the mixture, contributing to the bars’ final texture.

4-Fourth Step: Add eggs and vanilla. Add the two large eggs (at room temperature) and vanilla extract to the butter-sugar mixture. Whisk well for about 1 minute until the mixture is smooth and glossy. This step is important for emulsifying the ingredients and creating the proper structure for your Chocolate Chip Cookie Bars.

5-Fifth Step: Combine wet and dry ingredients. Add the dry flour mixture to the wet ingredients. Using a silicone spatula, stir until almost fully combined. It’s okay if there are still some dry streaks visible in the dough. Overmixing at this stage can lead to tough bars, so stop mixing as soon as the ingredients are mostly incorporated.

6-Sixth Step: Add the chocolate chips. Reserve about ¼ cup of the chocolate chips for the top of the bars. Fold the remaining chocolate chips into the dough using your spatula, ensuring they are distributed evenly throughout. This technique guarantees that every bite of your Chocolate Chip Cookie Bars will have plenty of chocolate.

7-Seventh Step: Transfer dough to the pan. Dollop the dough into your prepared 8×8-inch pan. Using an offset spatula, spread the dough evenly across the pan. Leave some texture on top rather than making it perfectly smooth this creates appealing ridges that will bake beautifully. Sprinkle the reserved chocolate chips over the top, pressing them gently into the dough.

8-Eighth Step: Bake the bars. Place the pan in the preheated oven and bake for about 55 minutes. The bars are done when the edges are golden brown and a toothpick inserted in the center comes out with a few moist crumbs (not completely clean). For a gooier, brownie-like texture, reduce the baking time to about 45 minutes.

9-Final Step: Cool and cut the bars. Let the bars cool in the pan for about an hour before attempting to remove them. This cooling period allows them to set properly. Once cooled, use the parchment paper handles to lift the bars from the pan. Cut into squares using a large, straight-edged knife, wiping the knife clean between cuts for perfect slices. Your Chocolate Chip Cookie Bars are now ready to serve!