Combine 3 tablespoons butter and 2 tablespoons chocolate chips in a small bowl, then melt in the microwave for 20-30 seconds. Set aside.

In another bowl, combine remaining 1/2 tablespoon melted butter with 2 tablespoons of graham cracker crumbs and stir until moistened.

Press graham crumbs into the bottom of your mug.

In a bowl. whisk egg, sugar and vanilla until smooth.

Add in flour, baking powder, salt and cocoa, stir until a thick batter forms.

Stream in melted butter and chocolate, mixing to combine.

Fold in remaining 1 tablespoon chocolate chips.

Add half of the mixture on top of the graham crust in the mug.

Then add a few mini marshmallows (I did about 10) or you can add a scoop of marshmallow fluff instead.

Add remaining batter on top, then pop in the microwave for 1 minute and 20 seconds (I have a 1000 watt microwave).

Remove and top with a hearty scoop of marshmallow fluff.

Put back in the microwave for 5 seconds to melt it and make it ooey gooey.

Carefully remove from microwave (I set mine on a plate since the marshmallows can be messy) and sprinkle with graham cracker crumbs!

Serve warm with a spoon and dig in!