Pre-heat oven to 375 degrees
In a medium sized mixing bowl add brownie mix, eggs, vegetable oil, vanilla, and salt, mix well. Spray a mini muffin tin with cooking spray and line with mini muffin liners. Scoop 1 teaspoon of brownie mix into each liner. Top brownie mix with graham cracker ( see notes below), a square of chocolate, and 3 mini marshmallows. Repeat on all 54. Bake at 375 degrees for 10 minutes or until brownie is cooked and marshmallow is golden brown.