In a medium mixing bowl, sift together cocoa powder, flour, baking soda and fine sea salt. Set aside.
In the bowl of a stand mixer fitted with the paddle attachment or a large mixing bowl with an electric hand mixer, cream together butter and brown sugar with a mixer until fluffy, approximately 5 minutes.
Add eggs, one at a time.
Add vanilla, blending until mixed.
Slowly add dry mixture until dough forms.
Fold in mini dehydrated marshmallows.
Cover and refrigerate for a minimum of 1 hour and up to 36 hours.
When ready to bake, preheat oven to 350 degrees. Line an insulated baking sheet with parchment paper.
Drop heaping tablespoons of cookie dough onto the cookie sheet.
Baking for 9-11 minutes and remove right before they look cooked.
Cool for 10 minutes before placing on a cooling rack and allowing to cool fully.
If you've tried this recipe, come back and let us know how it was!