Preheat oven to 325°F and grease a 8 x 8 inch baking pan/baking dish, lining it with parchment paper that overhangs for easy removal.

In a medium size sauce pan melt butter then remove from heat and whisk in cocoa powder followed by the sugar until well combined.

Whisk in eggs and the vanilla vigorously until smooth.

Stir in the flour, and salt and mix together well.

Spoon batter into the prepared pan. Use an offset spatula to smooth batter evenly.

Bake 25 to 30 minutes, or until cooked through and toothpick or tester comes out mostly clean with a couple crumbs.

While brownies are baking, make peanut butter filling. In a mixing bowl, combined melted butter, peanut butter until smooth or mostly smooth.

Stir in vanilla, and gradually stir and fold in powdered sugar 1 tablespoon at a time, stirring in a teaspoon of milk as needed to incorporate the sugar fully.

Remove brownies from oven when done baking.

Gently drop peanut butter filling onto top of warm brownies, using fingertips to make sure brownies are completely covered evenly.

For the ganache, in a small microwave-safe bowl, or small saucepan, combine and melt chocolate chips and butter. Heat over low heat or in short 20-30 second spurts in the microwave for 1-2 minutes stirring gently in between.

Stir until smooth.

Pour over peanut butter layer and spread until evenly distributed with an offset spatula.

Refrigerate brownies for 2 hours (or more). Cut into bars while chilled. Serve and enjoy!