In a small bowl, combine 3 tablespoons butter and 1 oz of chocolate and melt in the microwave for 20-30 seconds, set aside.

In another bowl, melt ½ tablespoon butter then add 3 tablespoon of graham cracker crumbs and stir until moistened, then press graham crumbs into bottom of mug.

In another bowl, whisk egg, sugar, vanilla until smooth. Then add flour, cocoa, baking powder, salt, and mix until well combined.

Add half of the batter in the mug, followed by a handful of mini marshmallow. Add remaining batter on top and microwave for 1 minutes and 40 seconds. Remove and top with additional marshmallows and microwave for 15-20 seconds. Sprinkle with graham crumbs!