First, preheat the oven to 350
With an electric mixer cream together 1 cup of butter, sugar and vanilla.
In a seperate bowl combine the flour, cocoa powder, baking powder, baking soda and salt.
Gradually add the flour mixure to the butter mixture alternating with the milk until it is all well incorporated.
This dough is fairly dry but if it is too dry and not sticking together add in more milk a tsp at a time until it is no longer crumbly.
Using a spoon or dough scoop, scoop out dough and roll it into balls. Using the bottom of a glass press the dough to about 1/4 of an inch thick. This techinque creates cookies with a rougher edge. For a smoother edge flatten and form the cookies with your hands.
Bake for 11-13 minutes or until the tops appear dry, allow them to cool for 3 minutes on the cookie sheet before removing to a wire cooling rack to cool completely.
Once the cookies are fully cooled they are ready to frost.
In a medium saucepan combine the cocoa powder, powdered sugar, 6 Tbsp. butter, milk, and salt. Heat over medium heat until butter is melted and everything is well mixed and smooth.
Working with one cookie at a time spoon frosting on and quickly top with marshmallow bits. The frosting sets quickly this allows the marshmallows to stick. If you’re using other toppings you’ll want to do it this way too! If the frosting thickens too much while frosting the cookies just re-heat it until it softens.
Once all the cookies are frosted and decorated allow the frosting to set and then put them in an air tight container (or eat them!!)