Preheat your oven to 350°F (175°C). Line a 9x13-inch baking pan with parchment paper or foil, leaving an overhang on the sides. You can also lightly spray the bottom with cooking spray if you prefer.
In a medium bowl, whisk together the all-purpose flour, baking soda, and kosher salt. Set this mixture aside for a moment.
In a larger mixing bowl, combine the melted and slightly cooled butter with both brown sugar and white sugar. Stir them thoroughly until smooth and well-combined.
Beat in the eggs one at a time, ensuring each is fully incorporated before adding the next. Stir in the vanilla extract until fragrant.
Gradually add the dry flour mixture to the wet ingredients. Mix on low speed, or by hand, until just combined. Be careful not to overmix the dough.
Fold in the chocolate chips until they are evenly distributed throughout the dough. If you like, save a few to sprinkle on top before baking for a prettier finish.
Transfer the cookie dough into your prepared baking pan. Use a spatula or your hands to press the dough evenly into the bottom of the pan. Make sure it's spread from edge to edge.
Place the pan in the preheated oven. Bake for 25-35 minutes, or until the edges are golden brown and the center looks set but still slightly soft. A perfectly baked cookie bar will seem a little underdone in the middle when you pull it out.
Let them cool completely in the pan on a wire rack. Seriously, resist the urge to cut into them warm. They will continue to set up as they cool. Cutting them hot will result in a gooey, crumbly mess.
Once fully cooled, use the parchment paper overhang to lift the entire slab out of the pan. Place it on a cutting board and slice into squares or rectangles. Now, your delicious dessert bars are ready to enjoy!