Preheat your oven to 350°F (175°C).
Grease your baking pan with a little butter or line it with parchment paper.
Cream together the room temperature butter and sugar until light and fluffy.
Beat in the eggs, one at a time, mixing well after each addition. Stir in the vanilla extract until combined.
Whisk together the all-purpose flour, salt, cocoa powder, and optional chocolate chips in a separate bowl.
Gradually fold the dry ingredients into the wet ingredients until just combined.
Spread the brownie batter evenly in the prepared baking pan.
Combine the creamy peanut butter and powdered sugar in a clean bowl, mixing until smooth.
Dollop the peanut butter mixture over the brownie batter and carefully spread it out.
Combine the crushed pretzel pieces with the melted butter in another bowl.
Sprinkle the pretzel mixture evenly over the peanut butter layer.
Bake in the preheated oven for 25-30 minutes.
Allow the brownies to cool in the pan for at least 15 minutes before transferring them to a wire rack.
