Instructions

1. Preheat your oven to 350°F. Line a baking sheet with parchment paper and set aside.
2. In a stand mixer fit with paddle attachment, cream the butter and sugars together until the mixture becomes light and airy, about 2 minutes. Scrape down the bowl and add in the egg and vanilla, beating until well combined.
3. In another bowl, sift together the flour, cocoa powder, espresso powder, baking soda, and salt. Next, add the dry ingredients into the butter mixture, stirring until just combined. Gently fold in the chocolate chips, being careful not to over mix the dough.
4. Spoon about 1/4 of the fluff into the batter and fold once or twice. You fluff will get marbled and incorporate into the dough when you scoop the cookies out, so you want to make sure not to over mix the fluff in. Use a large cookie scoop to scoop out about 1 inch cookie dough spheres around the areas of the dough that has fluff in it. Place the cookies on the prepared cookie sheet about 2 inches apart. Continue to add in the marshmallow fluff in increments every few cookies to make sure each cookie has a good amount of fluff without over incorporating the fluff. Bake for 10-12 minutes, being sure to keep an eye on the bake as every oven is different. The key is a soft center, but a firmer edge. Let cool on a rack for 10 minutes before serving.
   Devour.