Preheat your oven to 350°F (175°C). Grease a 9x13 inch baking pan with butter or line it with parchment paper.

In a medium mixing bowl, whisk together 1 ½ cups all-purpose flour, 1 teaspoon baking soda, and ½ teaspoon salt. Set aside.

In a large mixing bowl, cream together ½ cup unsalted butter, ¾ cup light brown sugar, and ½ cup granulated sugar using an electric mixer until light and fluffy.

Add in 2 large eggs and 1 teaspoon vanilla extract. Mix on low speed until fully incorporated.

Gradually add the dry mixture into the wet batter, mixing gently until just combined. Fold in 1 cup chunky peanut butter, 1 cup semi-sweet chocolate chips, and 1 cup coarsely chopped pretzels.

Spread the batter evenly in the baking pan.

Bake for 30-35 minutes, or until edges are golden and a toothpick inserted comes out with a few moist crumbs.

Let cool in the pan for 10 minutes before transferring to a wire rack to cool completely.

Before slicing, top with additional chopped pretzels, peanut butter chips, and chocolate chips.

Slice into generous squares and serve.