Preheat oven to 350 degrees.

Line a 9x13 baking pan with foil and spray well with non stick cooking spray. Leave some overhang so you can remove brownies from the pan after baking.

In a small saucepan, melt butter and chocolate chips together over low heat and set aside to cool.

Once cooled, transfer chocolate and butter mixture to a large mixing bowl and add sugar, stirring well.

Then add eggs and vanilla and continue stirring until completely combined.

Stir in flour, cocoa powder and salt.

Spread batter evenly in baking dish and gently press peanut butter cups into brownie batter.

Bake about 30 minutes.

Let brownies cool, remove brownies from pan using foil edges and cut into squares.