Add cooled melted butter and brown sugar to the stand mixer bowl and beat with the paddle attachment for 2-3 minutes until light in color and creamy.

Add the egg, vanilla extract, and continue beating for another 2-3 minutes until fluffy.

In another mixing bowl, sift together the flour, cocoa powder, baking soda, and baking powder. Stir in the kosher salt and give it a good mix to distribute. Add the flour mixture to the wet ingredient mixture in the stand mixer bowl, stir until incorporated. Stop the mixer and scrape down the sides and bottom of the bowl as necessary.

Add the chocolate chips, mini marshmallows and stir to incorporate. Stop the mixer and scrape down the bowl with a spatula and give it another good mix as needed.

Portion the cookie dough with a large cookie scoop and place them on a parchment lined baking sheet. Press 3-4 mini marshmallows on top of the cookie dough ball.

Preheat the oven to 350°F.

Place 6 dough balls on a baking sheet, about 2 inches apart, and bake 1 batch at a time for 15 minutes.

The cookies may spread a little bit, so as soon as you remove them from the oven, immediately place a round cookie cutter larger than your cookie over each baked cookie and swirl it around in a circular motion as if swirling a glass of wine to make them perfectly round.

Allow the cookies to cool on the baking sheet for 10-15 minutes before removing them to a wire rack to cool completely.