Preheat oven to 350 degrees F. Line an 8×8″ square baking pan with parchment paper or foil. If using foil, spray it with cooking spray.

In medium bowl, combine flour, 2 Tablespoons cocoa powder, and 1/2 teaspoon salt. Set aside.

In large mixing bowl, beat together 1/2 cup butter, sugar, and 3/4 teaspoons vanilla until creamy. Add the eggs one at a time. Stir dry ingredients into batter. Pour batter into prepared pan and spread evenly. Sprinkle with chocolate chips. Bake in preheated oven for 22-25 minutes.

When brownie layer is done baking, combine peanut butter and oil in a microwave safe bowl or measuring cup and microwave on high for 20 seconds to soften. Pour this warm mixture over hot brownie and spread. Sprinkle the peanut butter covered brownies with marshmallows. Return to oven to bake for 3 more minutes, or until the marshmallows puff. Remove from oven and sprinkle puffed marshmallows with toasted pecans.

To make frosting, combine confectioners sugar and salt. In small saucepan, melt 4 Tablespoons butter over medium heat. When butter is melted, add the 2 Tablespoons of cocoa powder and 1/4 cup of the milk and heat until the mixture begins to boil. Pour this mixture into confectioners sugar/salt mixture and beat on high speed with an electric mixer until smooth and glossy. If frosting is not pourable at this point, add remaining 2 Tablespoons of milk (I didn’t have to do this). Lastly, beat in 1/4 teaspoon vanilla, then pour evenly over puffed marshmallows and pecans.

Let cool completely in refrigerator for 1-2 hours. Cut into squares and enjoy!