01 - Preheat oven to 350°F and grease a mini muffin pan thoroughly.
02 - In a mixing bowl, blend granulated sugar with melted unsalted butter until incorporated.
03 - Add large eggs and vanilla extract to the mixture, stirring until homogeneous.
04 - Sift in unsweetened cocoa powder, all-purpose flour, salt, and baking powder. Gently fold dry ingredients into the wet mixture just until combined.
05 - Fill each cup of the greased mini muffin pan approximately two-thirds full with brownie batter.
06 - Bake in preheated oven for 20 to 25 minutes or until a toothpick inserted in the center emerges clean.
07 - Remove pan from oven and promptly sprinkle chocolate chips over each brownie bite while hot.
08 - Distribute mini marshmallows and graham cracker crumbs evenly on top of the chocolate layer.
09 - Switch oven setting to broil. Return pan to oven and broil brownie bites for 1 to 2 minutes until marshmallows are golden brown and toasted to your preference.
10 - Allow brownie bites to cool slightly in the pan before removing and serving.