Chewy Small Batch Chocolate Chip Cookie Bars

Preheat the oven to 350°F (177°C). Grease a loaf pan with baking spray or neutral oil. Line the bottom and sides of the pan with parchment paper, leaving a slight overhang. Set aside.

Add the melted butter and brown sugar to a medium mixing bowl. Whisk until smooth, about 1 minute. Then, mix in the egg yolk and vanilla extract. Whisk until the mixture is thickened and lighter in color, another 1-2 minutes.

Next, add the flour, cornstarch, baking powder, and salt. Fold the dry ingredients into the wet ingredients until the batter is about 75% mixed. Then, fold the the semi-sweet chocolate chips into the batter until there are no more streaks of flour. Don't over-mix!

Evenly spread the batter into the prepared loaf pan. Sprinkle extra chocolate chips on top, if desired. Bake the cookie bars for 18-20 minutes, or until the edges are set and the centers are still a bit under-done. Don't over-bake or the bars will come out dry!

Let the cookie bars cool in the pan completely. Then, run a butter knife around the edge of the bars. Use the parchment paper to carefully release the cookie bars from the pan. Cut them into 6-8 bars and enjoy!