In a medium bowl, melt the butter in the microwave. It should just be melted! Then add the brown and white sugar. Whisk to combine.
½ cup unsalted butter, 1 stick, ¾ cup dark brown sugar, ¼ cup white sugar
Add the room temperature egg and vanilla extract and whisk to combine them into the butter and sugar.
1 large egg, room temperature, 1 teaspoon vanilla extract
Add the cocoa powder, flour, baking powder, baking soda, chocolate chips, graham cracker crumbs, and mix with a spoon to combine.
½ teaspoon baking soda, 1 cup all-purpose flour, ⅓ cup cocoa powder, ⅓ cup crushed grahama cracker crumbs, ¼ cup semi-sweet chocolate chips, ½ teaspoon baking powder
Using a large cookie scoop, scoop the cookies on to a parchment lined baking tray, there should be about 8 cookies. Then take the marshmallow fluff from the fridge. If the marshmallow is still really sticky, spray your hands with some non stick cooking spray before handling. Then rip off about 1 tablespoon pieces of marshmallow and place it on top of the dough ball.
½ cup homemade or store bought marshmallow fluff
Using your hands, cup the dough up and around the sides of the marshmallow so that you can still see the top of it, but its encased completely in the dough. This will prevent the marshmallow from oozing out of the cookie while its baking.
Once all the dough balls have been stuffed with the marshmallow, place them back on the parchment lined tray and sprinkle them with extra graham crumbs. Place the tray in the fridge for at least 45 minutes to an hour.
Then preheat the oven to 350 and bake the cookies for 12-13 minutes. Let them cool completely before removing. Enjoy!