Preheat your oven to 350°F (175°C) and line an 8x8 inch baking dish with parchment paper.

Melt ½ cup of unsalted butter in a medium-sized microwave-safe bowl.

Stir in ¾ cup of crunchy peanut butter until smooth.

Incorporate 1 cup of brown sugar, 2 large eggs, and 1 teaspoon of vanilla extract, whisking until smooth.

In a separate bowl, mix 1 cup of all-purpose flour, ½ teaspoon of baking soda, ¼ teaspoon of cornstarch, and a pinch of kosher salt.

Combine the dry ingredients into the wet mixture, stirring gently until just mixed.

Fold in 1 cup of semi-sweet chocolate chips, then spread the batter into the prepared baking dish.

Bake for 25–30 minutes until golden brown, and a toothpick comes out with moist crumbs.

Let cool in the pan for 10 minutes, then remove and cool completely before slicing into 12 pieces.