Preheat the oven to 350° degrees Fahrenheit and spray an 8x8" baking dish with a non stick cooking spray.

Add the brown sugar and butter into a bowl and use a hand or stand mixer to beat together until creamy.

Add in the egg and vanilla extract and mix well.

Now mix in the flour and baking powder.

Fold in your chocolate chips, marshmallows, and graham crackers.

Pour the mixture into the baking dish and press the dough evenly into the bottom.

Bake for 25 minutes, let cool, and slice into squares.