Step 1

Preheat the oven to 350°F and line a square pan (9 x 9 or 8 x 8 will both work), with parchment paper. Set aside.

Step 2

In a stand mixer fit with the paddle attachment, beat together the butter and peanut butter until homogenous. Don’t over mix.

Step 3

Add the brown sugar and mix well. Scrape down the bowl and add the egg and vanilla extract. Mix until combined.

Step 4

Scrape down the bowl and add the flour, graham cracker crumbs, baking soda, and salt. Mix until combined and no streaks of flour remain.

Step 5

Add the marshmallows and chocolate pieces and fold once or twice to distribute throughout the batter. Transfer the batter to the prepared baking pan and pat into an even layer.

Step 6

Bake for 20 to 30 minutes or until set on the edges and a knife inserted into the middle comes out mostly clean.  Allow to cool before slicing into 16 pieces. Enjoy!