The ultimate carving cookie!! I found this on another site and made a few small changes and this quickly became my favorite cookie. CAUTION: You may need to double the recipe unless you have enough will power to not taste the dough!!
Preheat the oven to 375 degrees F (190 degrees C). Grease cookie sheets.
In a large bowl, cream together butter, brown sugar and white sugar until smooth.
Beat in the eggs one at a time, then stir in the vanilla.
Combine the flour, cocoa, baking soda and salt; stir into the creamed mixture.
Mix in the chocolate chips and marshmallows.
Drop by rounded spoonfuls onto the prepared cookie sheets about 2 inches apart. These will spread quite a bit, so make sure the cookies are not too big.
Bake for 8 to 10 minutes in the preheated oven.
Allow cookies to cool on baking sheet for 5 minutes before removing to a wire rack to cool completely.