In a large bowl, beat the butter and sugar until it becomes light and fluffy.
Continue whisking while adding the eggs and vanilla extract.
In another bowl, sift the flour, baking soda, baking powder, salt and cocoa mixture.
Add the dry ingredients into the butter mixture and continue mixing with a spatula. (do not over mix)
Add the chocolate chips and marshmallows into the mixture and stir.
Put a stretch film on top of it and chill in the fridge for 1 hour
Put parchment paper on a baking tray and scoop the cookie dough with a spoon and place them intermittently.
Bake in a 180 C / 350 F pre-heated oven for 10 minutes.
Let the cookies rest for 5 minutes after taken from the oven.
Remove the cookies from the tray and continue to cool down.