Preheat your oven to 350 degrees Fahrenheit and spray a 9 x 13-inch baking dish with non-stick spray.
In a large bowl, prepare box of brownie mix according to package directions.
Pour brownie mix into the baking pan and bake according to box directions (20-25 minutes).
Allow the brownies to cool completely while you make the next layer.
In a mixing bowl, combine 1/2 cup of butter, peanut butter, and powdered sugar.
Using a hand mixer, beat on medium speed until well combined.
Drop the peanut butter mixture over the brownie layer in small spoonfuls.
Use an offset spatula or butter knife to spread the peanut butter mixture in an even layer over the brownies.
In a microwave-safe bowl, heat chocolate chips on 30 second intervals, stirring well between each set, until melted.
Stir in heavy cream and mix until its smooth ganache consistency.
Pour melted chocolate topping over the top of the peanut butter layer and spread evenly.
Chill the brownies in the refrigerator for at least 4 hours to allow the peanut butter center and the chocolate layer to firm up.
Slice the cooled brownies into squares and enjoy!