Preheat your oven to 350F. Prepare a cookie sheet with cooking spray. In a single layer, place 9-10 whole sheets of graham crackers.

Cream the butter, white sugar, and brown sugar together with a stand mixer - about 2 or 3 minutes until mixture becomes lighter in color and fluffy. Scrape down sides then slowly add the eggs in one at a time. Scrape sides of bowl after every few eggs are mixed in. Once fully incorporated, add the vanilla.

In a separate bowl, mix the flour, cocoa powder and salt.

Gradually add the dry ingredients to the batter mixture until combined. The batter should be thick and similar to a soft cookie dough. Do not over mix the batter. Stop mixing immediately once the dry ingredients are incorporated.

Spread the brownie batter evenly over the sheets of graham crackers. Bake for 25-30 minutes or until a toothpick poked into the center of the brownies comes out clean.

Once the brownies are done let them cool completely before adding the marshmallow fluff.

While the brownies are baking, using a double boiler heat egg whites, sugar and salt over simmering water. Make sure the bowl does not touch the simmering water. Stir mixture. Heat until mixture reaches 160F and sugar has dissolved (about 4-5 minutes). Test if sugar has dissolved by rubbing the mixture between two fingers. It should feel smooth with no grains.

When mixture is ready, wipe bottom of bowl with a towel to remove any moisture then carefully pour mixture into a stand mixer bowl equipped with a whisk attachment.

Whip egg white mixture on high until it turns white, glossy and significantly increases in volume (about 10 minutes). The mixture should be very thick and fluffy. During this time the mixture will begin to cool.

Once fully whipped, slowly add vanilla. Whip for an additional 1-2 minutes.

In a microwave-safe bowl, add chocolate chips and 1/4 cup cream. Heat in the microwave using 30 second intervals until chocolate begins to melt and cream is hot. (about 1 minute)

Whisk mixture in a small circular motion in the center. As the chocolate absorbs the cream widen your circular motion until all cream has been mixed in and the mixture is dark, rich and smooth.

If still very warm, let cool for a few minutes. Use a spoon or pour ganache into a ziploc/piping bag with a very small hole. Drizzle over brownies. 

Once the brownies have cooled evenly spread marshmallow fluff over the brownies. Using a kitchen torch or placing in the oven on broil for 1-2 minutes, toast the top of the marshmallow meringue until desired "toastiness" is reached.

Use a spoon or pour ganache into a ziploc/piping bag with a very small hole. Drizzle over brownies.

Garnish with a chunk of graham cracker and small square of Hershey chocolate bar in each piece.