Step 1: Preheat your oven to 350°F (175°C). Line a 9x13 inch baking pan with parchment paper, leaving an overhang on the long sides for easy removal.
Step 2: In a large bowl, using an electric mixer, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy, about 2-3 minutes.
Step 3: Add the peanut butter to the butter-sugar mixture and beat until well combined and smooth.
Step 4: Beat in the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.
Step 5: In a separate medium bowl, whisk together the all-purpose flour, baking soda, and salt.
Step 6: Gradually add the dry ingredients to the wet ingredients, mixing on low speed until just combined. Be careful not to overmix.
Step 7: Fold in 1 ½ cups of the chocolate chips into the dough until evenly distributed.
Step 8: Press the dough evenly into the prepared baking pan. Sprinkle the remaining ½ cup of chocolate chips over the top of the dough.
Step 9: Bake for 25-30 minutes, or until the edges are golden brown and a toothpick inserted into the center comes out with moist crumbs, not wet batter. The center may still look slightly soft.
Step 10: Remove the pan from the oven and let the bars cool completely in the pan on a wire rack before cutting into squares. This ensures they set properly and are easier to slice.