01 -
Preheat oven to 350°F. Line an 8 x 8 inch metal baking pan with parchment paper, ensuring overhang on two sides.
02 -
Fit graham cracker sheets evenly to cover the pan bottom. Break crackers as needed to fill any gaps.
03 -
In a microwave-safe mixing bowl, combine unsalted butter and semi-sweet chocolate chips. Heat in 30-second intervals, stirring after each until melted and thoroughly blended.
04 -
Stir in granulated sugar just to incorporate, then microwave mixture for an additional 1 minute. Whisk until sugar is fully combined. If needed, let cool for 5 minutes until mixture is warm but not hot.
05 -
Vigorously whisk in room temperature eggs for 1 minute until batter appears smooth and falls in ribbons from the whisk. Mix in vanilla extract, unsweetened or Dutch processed cocoa powder, and salt until glossy.
06 -
Whisk all-purpose flour into the batter until completely combined and smooth.
07 -
Spread brownie batter evenly over graham cracker base in prepared pan. Smooth top with a flexible spatula.
08 -
Bake the pan in preheated oven for 25 minutes. Remove pan carefully from oven.
09 -
Evenly scatter mini marshmallows over brownies, then top with roughly crushed graham cracker and Hershey’s chocolate bar pieces.
10 -
Return pan to oven and bake an additional 8 to 10 minutes, until marshmallows are lightly golden and toppings are set.
11 -
Allow brownies to cool in the pan for 1 hour, then use parchment paper overhang to lift from pan. Transfer to a cutting board, slice, and serve.