01 -
Whisk together flour, cocoa powder, baking soda, and salt in medium bowl.
02 -
Beat butter and sugar with electric mixer until light and fluffy, about 3-4 minutes.
03 -
Beat in eggs one at a time, then vanilla extract.
04 -
Gradually mix dry ingredients into wet until just combined. Chill dough for 1 hour.
05 -
Roll into balls, make indents, fill with marshmallow fluff and swirl. Bake at 350°F for 10-12 minutes.