Preheat your oven to 375°F (190°C).
Prepare a 9x13-inch baking pan by either greasing it or lining it with parchment. paper or foil for easy removal. If using foil, spray it with non-stick cooking spray to prevent sticking.
In a large mixing bowl, cream together ½ cup softened butter, ½ cup shortening, ¾ cup granulated sugar, and ¾ cup packed brown sugar. Mix on medium speed for about 3 minutes until smooth and fluffy.
Add 2 eggs and 1 teaspoon vanilla extract to the bowl and continue beating for another 2 minutes, until well combined.
Reduce the mixer speed to low and gradually add 2½ cups all-purpose flour, 1 teaspoon baking soda, and 1 teaspoon salt. Mix just until the dry ingredients are fully incorporated, scraping down the sides of the bowl as needed.
Fold in 2 cups chocolate chips until evenly distributed throughout the dough.
Spread the dough evenly into your prepared pan, smoothing it out with a spatula.
Bake for 15–20 minutes. For extra soft and chewy bars, remove them at the 15-minute mark—they may look slightly underbaked in the center, but they'll continue setting as they cool.
Cool completely in the pan before cutting into squares. To speed up the cooling process, place the pan in the refrigerator or freezer for a short time.