Preheat the oven to 350℉ and line a 9x9-inch pan with parchment paper, and spray with cooking spray.
Add the brown sugar, melted butter, eggs, and vanilla to a mixing bowl and whisk to combine.
Next, add the protein powder, flour, and salt to the bowl and stir to combine. Set aside.
Add ½ cup of chocolate chips to a small bowl and microwave on high for 20-second intervals, stirring and repeating until the chocolate chips are melted. Set aside.
Add the melted chocolate chips to the batter and mix until all the ingredients are combined.
Transfer the batter to the prepared baking dish. Top with the mini marshmallows, chocolate chips, and broken up graham crackers.
Bake in the oven for 10 minutes, cover with foil and bake for an additional 10 minutes.
Once the brownies are done baking, remove from the oven and allow to cool for 10 minutes before transferring from the baking dish.