Make the Brownie Layer:

• Preheat oven to 350°F (177°C). Line an 8-inch square baking pan with foil or parchment paper, leaving an overhang for easy removal. Grease with nonstick spray.
• In a large bowl, whisk together melted butter and sugar until combined. Add eggs and vanilla extract, whisking until smooth.
• Sift in cocoa powder, flour, and salt. Whisk until just combined.
• Pour batter into the pan and spread evenly.
• Bake for 23-28 minutes, or until a toothpick inserted comes out with a few moist crumbs. Let cool completely.

Make the Peanut Butter Fudge Layer:

• In a microwave-safe bowl, heat peanut butter and butter in 30-second increments, stirring until smooth.
• Stir in vanilla extract and salt.
• Add powdered sugar in three additions, mixing well each time. The final mixture will be thick—knead it with your hands if necessary.
• Flatten pieces of the peanut butter mixture with your hands and place over the cooled brownies. Smooth into an even layer.

Make the Chocolate Topping:

• In a microwave-safe bowl, heat chocolate chips and butter in 30-second intervals at 50% power, stirring between each, until smooth.
• Pour over the peanut butter layer and smooth evenly.
• Refrigerate for 45 minutes to 1 hour, until the chocolate sets.

Slice & Serve:

• Lift brownies out of the pan using the parchment overhang. Slice into bars and enjoy!